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1 Materials Beyond Silicon Materials Beyond Silicon By Uma Aghoram
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1
Materials Beyond SiliconMaterials Beyond Silicon
By Uma Aghoram
2
TI Fellows Forum
Moorersquos LawMoorersquos Lawbull MSI LSI VLSI
bull Moorersquos Law states that the number of transistors on a chip doubles about every two years
bull At each stage of scaling fundamental limits are being reached
3
TI Fellows Forum
SCALING LIMITSSCALING LIMITSbull Lithographic Limits
ndash XRay and E-beam in futurebull Short channel effects
ndash Vt roll offndash DIBL
bull Oxide thickness scaling reaching a few atomic layers of siliconndash Large leakage currentsndash Higher power dissipation
4
TI Fellows Forum
Exponential Forever Exponential Forever
130nm1048764104876490nm1048764104876460nm1048764104876445nm1048764104876430nm10487641048764
5
TI Fellows Forum
KEEPING MOORErsquoS LAW ALIVEKEEPING MOORErsquoS LAW ALIVE
bull Strained Silicon
bull Novel Device structures
bull High K dielectrics
bull Carbon Nanotubes SET
bull Alternate channel materials
6
TI Fellows Forum
REPLACING SILICONREPLACING SILICON
bull Cost effective
bull Easy incorporation into existing technology
bull Reliable oxide
bull Performance enhancement
7
TI Fellows Forum
GermaniumGermaniumADVANTAGESbull Has high electron and hole mobility as compared to silicon ndash
High speed
bull high-K dielectricsbull Good compatibility with III-V materialsDISADVANTAGESbull No reliable native oxidebull Small Bandgap may lead to larger tunneling currents
Material n h
Silicon 1450 500Germanium 3900 2270
8
TI Fellows Forum
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterialsADVANTAGESbull Has 6X larger electron mobility as compared to
silicon ndash High speed
bull Have excellent Optoelectronic propertiesbull High resistance to radiation damagebull High flexibility to forming alloysbull Heat resistant
Material n h
Silicon 1450 500GaAs 9200 400
9
TI Fellows Forum
DISADVANTAGESbull No reliable native oxidebull Composite nature leads to high defect density-
Unstable Vtbull More expensive to manufacture pure GaAs to meet
industry standardbull Lower thermal conductivity than Siliconbull More fragilebull More quantum effectsbull Small recombination time results in poor performance
of GaAs BJTsbull High leakage current in narrow gap III-V materials
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterials
10
TI Fellows Forum
Where do we standWhere do we standGermaniumbull Strained Si Mosfets with SiGe layers have been
manufacturedbull Dual channel heterostructure MOSFETS are
being researchedGallium Arsenidebull Bell Labs and Freescale recently reported that
they have grown high quality Ga2O3 on GaAs with low interface states and achieved enhancement and depletion mode MOSFETs
bull HBTrsquos HEMT Power transistor
11
TI Fellows Forum
Toy ProblemToy Problem
bull Position of charge centroid in a MOSCAP for three different materials namelyndash Siliconndash Germaniumndash Gallium Arsenide
bull The position where the charge peaks is of relevance as it determines additional thickness of the dielectric and effectiveness of gate control of device
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
2
TI Fellows Forum
Moorersquos LawMoorersquos Lawbull MSI LSI VLSI
bull Moorersquos Law states that the number of transistors on a chip doubles about every two years
bull At each stage of scaling fundamental limits are being reached
3
TI Fellows Forum
SCALING LIMITSSCALING LIMITSbull Lithographic Limits
ndash XRay and E-beam in futurebull Short channel effects
ndash Vt roll offndash DIBL
bull Oxide thickness scaling reaching a few atomic layers of siliconndash Large leakage currentsndash Higher power dissipation
4
TI Fellows Forum
Exponential Forever Exponential Forever
130nm1048764104876490nm1048764104876460nm1048764104876445nm1048764104876430nm10487641048764
5
TI Fellows Forum
KEEPING MOORErsquoS LAW ALIVEKEEPING MOORErsquoS LAW ALIVE
bull Strained Silicon
bull Novel Device structures
bull High K dielectrics
bull Carbon Nanotubes SET
bull Alternate channel materials
6
TI Fellows Forum
REPLACING SILICONREPLACING SILICON
bull Cost effective
bull Easy incorporation into existing technology
bull Reliable oxide
bull Performance enhancement
7
TI Fellows Forum
GermaniumGermaniumADVANTAGESbull Has high electron and hole mobility as compared to silicon ndash
High speed
bull high-K dielectricsbull Good compatibility with III-V materialsDISADVANTAGESbull No reliable native oxidebull Small Bandgap may lead to larger tunneling currents
Material n h
Silicon 1450 500Germanium 3900 2270
8
TI Fellows Forum
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterialsADVANTAGESbull Has 6X larger electron mobility as compared to
silicon ndash High speed
bull Have excellent Optoelectronic propertiesbull High resistance to radiation damagebull High flexibility to forming alloysbull Heat resistant
Material n h
Silicon 1450 500GaAs 9200 400
9
TI Fellows Forum
DISADVANTAGESbull No reliable native oxidebull Composite nature leads to high defect density-
Unstable Vtbull More expensive to manufacture pure GaAs to meet
industry standardbull Lower thermal conductivity than Siliconbull More fragilebull More quantum effectsbull Small recombination time results in poor performance
of GaAs BJTsbull High leakage current in narrow gap III-V materials
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterials
10
TI Fellows Forum
Where do we standWhere do we standGermaniumbull Strained Si Mosfets with SiGe layers have been
manufacturedbull Dual channel heterostructure MOSFETS are
being researchedGallium Arsenidebull Bell Labs and Freescale recently reported that
they have grown high quality Ga2O3 on GaAs with low interface states and achieved enhancement and depletion mode MOSFETs
bull HBTrsquos HEMT Power transistor
11
TI Fellows Forum
Toy ProblemToy Problem
bull Position of charge centroid in a MOSCAP for three different materials namelyndash Siliconndash Germaniumndash Gallium Arsenide
bull The position where the charge peaks is of relevance as it determines additional thickness of the dielectric and effectiveness of gate control of device
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
3
TI Fellows Forum
SCALING LIMITSSCALING LIMITSbull Lithographic Limits
ndash XRay and E-beam in futurebull Short channel effects
ndash Vt roll offndash DIBL
bull Oxide thickness scaling reaching a few atomic layers of siliconndash Large leakage currentsndash Higher power dissipation
4
TI Fellows Forum
Exponential Forever Exponential Forever
130nm1048764104876490nm1048764104876460nm1048764104876445nm1048764104876430nm10487641048764
5
TI Fellows Forum
KEEPING MOORErsquoS LAW ALIVEKEEPING MOORErsquoS LAW ALIVE
bull Strained Silicon
bull Novel Device structures
bull High K dielectrics
bull Carbon Nanotubes SET
bull Alternate channel materials
6
TI Fellows Forum
REPLACING SILICONREPLACING SILICON
bull Cost effective
bull Easy incorporation into existing technology
bull Reliable oxide
bull Performance enhancement
7
TI Fellows Forum
GermaniumGermaniumADVANTAGESbull Has high electron and hole mobility as compared to silicon ndash
High speed
bull high-K dielectricsbull Good compatibility with III-V materialsDISADVANTAGESbull No reliable native oxidebull Small Bandgap may lead to larger tunneling currents
Material n h
Silicon 1450 500Germanium 3900 2270
8
TI Fellows Forum
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterialsADVANTAGESbull Has 6X larger electron mobility as compared to
silicon ndash High speed
bull Have excellent Optoelectronic propertiesbull High resistance to radiation damagebull High flexibility to forming alloysbull Heat resistant
Material n h
Silicon 1450 500GaAs 9200 400
9
TI Fellows Forum
DISADVANTAGESbull No reliable native oxidebull Composite nature leads to high defect density-
Unstable Vtbull More expensive to manufacture pure GaAs to meet
industry standardbull Lower thermal conductivity than Siliconbull More fragilebull More quantum effectsbull Small recombination time results in poor performance
of GaAs BJTsbull High leakage current in narrow gap III-V materials
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterials
10
TI Fellows Forum
Where do we standWhere do we standGermaniumbull Strained Si Mosfets with SiGe layers have been
manufacturedbull Dual channel heterostructure MOSFETS are
being researchedGallium Arsenidebull Bell Labs and Freescale recently reported that
they have grown high quality Ga2O3 on GaAs with low interface states and achieved enhancement and depletion mode MOSFETs
bull HBTrsquos HEMT Power transistor
11
TI Fellows Forum
Toy ProblemToy Problem
bull Position of charge centroid in a MOSCAP for three different materials namelyndash Siliconndash Germaniumndash Gallium Arsenide
bull The position where the charge peaks is of relevance as it determines additional thickness of the dielectric and effectiveness of gate control of device
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
4
TI Fellows Forum
Exponential Forever Exponential Forever
130nm1048764104876490nm1048764104876460nm1048764104876445nm1048764104876430nm10487641048764
5
TI Fellows Forum
KEEPING MOORErsquoS LAW ALIVEKEEPING MOORErsquoS LAW ALIVE
bull Strained Silicon
bull Novel Device structures
bull High K dielectrics
bull Carbon Nanotubes SET
bull Alternate channel materials
6
TI Fellows Forum
REPLACING SILICONREPLACING SILICON
bull Cost effective
bull Easy incorporation into existing technology
bull Reliable oxide
bull Performance enhancement
7
TI Fellows Forum
GermaniumGermaniumADVANTAGESbull Has high electron and hole mobility as compared to silicon ndash
High speed
bull high-K dielectricsbull Good compatibility with III-V materialsDISADVANTAGESbull No reliable native oxidebull Small Bandgap may lead to larger tunneling currents
Material n h
Silicon 1450 500Germanium 3900 2270
8
TI Fellows Forum
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterialsADVANTAGESbull Has 6X larger electron mobility as compared to
silicon ndash High speed
bull Have excellent Optoelectronic propertiesbull High resistance to radiation damagebull High flexibility to forming alloysbull Heat resistant
Material n h
Silicon 1450 500GaAs 9200 400
9
TI Fellows Forum
DISADVANTAGESbull No reliable native oxidebull Composite nature leads to high defect density-
Unstable Vtbull More expensive to manufacture pure GaAs to meet
industry standardbull Lower thermal conductivity than Siliconbull More fragilebull More quantum effectsbull Small recombination time results in poor performance
of GaAs BJTsbull High leakage current in narrow gap III-V materials
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterials
10
TI Fellows Forum
Where do we standWhere do we standGermaniumbull Strained Si Mosfets with SiGe layers have been
manufacturedbull Dual channel heterostructure MOSFETS are
being researchedGallium Arsenidebull Bell Labs and Freescale recently reported that
they have grown high quality Ga2O3 on GaAs with low interface states and achieved enhancement and depletion mode MOSFETs
bull HBTrsquos HEMT Power transistor
11
TI Fellows Forum
Toy ProblemToy Problem
bull Position of charge centroid in a MOSCAP for three different materials namelyndash Siliconndash Germaniumndash Gallium Arsenide
bull The position where the charge peaks is of relevance as it determines additional thickness of the dielectric and effectiveness of gate control of device
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
5
TI Fellows Forum
KEEPING MOORErsquoS LAW ALIVEKEEPING MOORErsquoS LAW ALIVE
bull Strained Silicon
bull Novel Device structures
bull High K dielectrics
bull Carbon Nanotubes SET
bull Alternate channel materials
6
TI Fellows Forum
REPLACING SILICONREPLACING SILICON
bull Cost effective
bull Easy incorporation into existing technology
bull Reliable oxide
bull Performance enhancement
7
TI Fellows Forum
GermaniumGermaniumADVANTAGESbull Has high electron and hole mobility as compared to silicon ndash
High speed
bull high-K dielectricsbull Good compatibility with III-V materialsDISADVANTAGESbull No reliable native oxidebull Small Bandgap may lead to larger tunneling currents
Material n h
Silicon 1450 500Germanium 3900 2270
8
TI Fellows Forum
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterialsADVANTAGESbull Has 6X larger electron mobility as compared to
silicon ndash High speed
bull Have excellent Optoelectronic propertiesbull High resistance to radiation damagebull High flexibility to forming alloysbull Heat resistant
Material n h
Silicon 1450 500GaAs 9200 400
9
TI Fellows Forum
DISADVANTAGESbull No reliable native oxidebull Composite nature leads to high defect density-
Unstable Vtbull More expensive to manufacture pure GaAs to meet
industry standardbull Lower thermal conductivity than Siliconbull More fragilebull More quantum effectsbull Small recombination time results in poor performance
of GaAs BJTsbull High leakage current in narrow gap III-V materials
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterials
10
TI Fellows Forum
Where do we standWhere do we standGermaniumbull Strained Si Mosfets with SiGe layers have been
manufacturedbull Dual channel heterostructure MOSFETS are
being researchedGallium Arsenidebull Bell Labs and Freescale recently reported that
they have grown high quality Ga2O3 on GaAs with low interface states and achieved enhancement and depletion mode MOSFETs
bull HBTrsquos HEMT Power transistor
11
TI Fellows Forum
Toy ProblemToy Problem
bull Position of charge centroid in a MOSCAP for three different materials namelyndash Siliconndash Germaniumndash Gallium Arsenide
bull The position where the charge peaks is of relevance as it determines additional thickness of the dielectric and effectiveness of gate control of device
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
6
TI Fellows Forum
REPLACING SILICONREPLACING SILICON
bull Cost effective
bull Easy incorporation into existing technology
bull Reliable oxide
bull Performance enhancement
7
TI Fellows Forum
GermaniumGermaniumADVANTAGESbull Has high electron and hole mobility as compared to silicon ndash
High speed
bull high-K dielectricsbull Good compatibility with III-V materialsDISADVANTAGESbull No reliable native oxidebull Small Bandgap may lead to larger tunneling currents
Material n h
Silicon 1450 500Germanium 3900 2270
8
TI Fellows Forum
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterialsADVANTAGESbull Has 6X larger electron mobility as compared to
silicon ndash High speed
bull Have excellent Optoelectronic propertiesbull High resistance to radiation damagebull High flexibility to forming alloysbull Heat resistant
Material n h
Silicon 1450 500GaAs 9200 400
9
TI Fellows Forum
DISADVANTAGESbull No reliable native oxidebull Composite nature leads to high defect density-
Unstable Vtbull More expensive to manufacture pure GaAs to meet
industry standardbull Lower thermal conductivity than Siliconbull More fragilebull More quantum effectsbull Small recombination time results in poor performance
of GaAs BJTsbull High leakage current in narrow gap III-V materials
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterials
10
TI Fellows Forum
Where do we standWhere do we standGermaniumbull Strained Si Mosfets with SiGe layers have been
manufacturedbull Dual channel heterostructure MOSFETS are
being researchedGallium Arsenidebull Bell Labs and Freescale recently reported that
they have grown high quality Ga2O3 on GaAs with low interface states and achieved enhancement and depletion mode MOSFETs
bull HBTrsquos HEMT Power transistor
11
TI Fellows Forum
Toy ProblemToy Problem
bull Position of charge centroid in a MOSCAP for three different materials namelyndash Siliconndash Germaniumndash Gallium Arsenide
bull The position where the charge peaks is of relevance as it determines additional thickness of the dielectric and effectiveness of gate control of device
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
7
TI Fellows Forum
GermaniumGermaniumADVANTAGESbull Has high electron and hole mobility as compared to silicon ndash
High speed
bull high-K dielectricsbull Good compatibility with III-V materialsDISADVANTAGESbull No reliable native oxidebull Small Bandgap may lead to larger tunneling currents
Material n h
Silicon 1450 500Germanium 3900 2270
8
TI Fellows Forum
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterialsADVANTAGESbull Has 6X larger electron mobility as compared to
silicon ndash High speed
bull Have excellent Optoelectronic propertiesbull High resistance to radiation damagebull High flexibility to forming alloysbull Heat resistant
Material n h
Silicon 1450 500GaAs 9200 400
9
TI Fellows Forum
DISADVANTAGESbull No reliable native oxidebull Composite nature leads to high defect density-
Unstable Vtbull More expensive to manufacture pure GaAs to meet
industry standardbull Lower thermal conductivity than Siliconbull More fragilebull More quantum effectsbull Small recombination time results in poor performance
of GaAs BJTsbull High leakage current in narrow gap III-V materials
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterials
10
TI Fellows Forum
Where do we standWhere do we standGermaniumbull Strained Si Mosfets with SiGe layers have been
manufacturedbull Dual channel heterostructure MOSFETS are
being researchedGallium Arsenidebull Bell Labs and Freescale recently reported that
they have grown high quality Ga2O3 on GaAs with low interface states and achieved enhancement and depletion mode MOSFETs
bull HBTrsquos HEMT Power transistor
11
TI Fellows Forum
Toy ProblemToy Problem
bull Position of charge centroid in a MOSCAP for three different materials namelyndash Siliconndash Germaniumndash Gallium Arsenide
bull The position where the charge peaks is of relevance as it determines additional thickness of the dielectric and effectiveness of gate control of device
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
8
TI Fellows Forum
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterialsADVANTAGESbull Has 6X larger electron mobility as compared to
silicon ndash High speed
bull Have excellent Optoelectronic propertiesbull High resistance to radiation damagebull High flexibility to forming alloysbull Heat resistant
Material n h
Silicon 1450 500GaAs 9200 400
9
TI Fellows Forum
DISADVANTAGESbull No reliable native oxidebull Composite nature leads to high defect density-
Unstable Vtbull More expensive to manufacture pure GaAs to meet
industry standardbull Lower thermal conductivity than Siliconbull More fragilebull More quantum effectsbull Small recombination time results in poor performance
of GaAs BJTsbull High leakage current in narrow gap III-V materials
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterials
10
TI Fellows Forum
Where do we standWhere do we standGermaniumbull Strained Si Mosfets with SiGe layers have been
manufacturedbull Dual channel heterostructure MOSFETS are
being researchedGallium Arsenidebull Bell Labs and Freescale recently reported that
they have grown high quality Ga2O3 on GaAs with low interface states and achieved enhancement and depletion mode MOSFETs
bull HBTrsquos HEMT Power transistor
11
TI Fellows Forum
Toy ProblemToy Problem
bull Position of charge centroid in a MOSCAP for three different materials namelyndash Siliconndash Germaniumndash Gallium Arsenide
bull The position where the charge peaks is of relevance as it determines additional thickness of the dielectric and effectiveness of gate control of device
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
9
TI Fellows Forum
DISADVANTAGESbull No reliable native oxidebull Composite nature leads to high defect density-
Unstable Vtbull More expensive to manufacture pure GaAs to meet
industry standardbull Lower thermal conductivity than Siliconbull More fragilebull More quantum effectsbull Small recombination time results in poor performance
of GaAs BJTsbull High leakage current in narrow gap III-V materials
Gallium Arsenide and other III-V Gallium Arsenide and other III-V materialsmaterials
10
TI Fellows Forum
Where do we standWhere do we standGermaniumbull Strained Si Mosfets with SiGe layers have been
manufacturedbull Dual channel heterostructure MOSFETS are
being researchedGallium Arsenidebull Bell Labs and Freescale recently reported that
they have grown high quality Ga2O3 on GaAs with low interface states and achieved enhancement and depletion mode MOSFETs
bull HBTrsquos HEMT Power transistor
11
TI Fellows Forum
Toy ProblemToy Problem
bull Position of charge centroid in a MOSCAP for three different materials namelyndash Siliconndash Germaniumndash Gallium Arsenide
bull The position where the charge peaks is of relevance as it determines additional thickness of the dielectric and effectiveness of gate control of device
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
10
TI Fellows Forum
Where do we standWhere do we standGermaniumbull Strained Si Mosfets with SiGe layers have been
manufacturedbull Dual channel heterostructure MOSFETS are
being researchedGallium Arsenidebull Bell Labs and Freescale recently reported that
they have grown high quality Ga2O3 on GaAs with low interface states and achieved enhancement and depletion mode MOSFETs
bull HBTrsquos HEMT Power transistor
11
TI Fellows Forum
Toy ProblemToy Problem
bull Position of charge centroid in a MOSCAP for three different materials namelyndash Siliconndash Germaniumndash Gallium Arsenide
bull The position where the charge peaks is of relevance as it determines additional thickness of the dielectric and effectiveness of gate control of device
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
11
TI Fellows Forum
Toy ProblemToy Problem
bull Position of charge centroid in a MOSCAP for three different materials namelyndash Siliconndash Germaniumndash Gallium Arsenide
bull The position where the charge peaks is of relevance as it determines additional thickness of the dielectric and effectiveness of gate control of device
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
12
TI Fellows Forum
AssumptionsAssumptionsbull One dimensional problembull One band effective mass Hamiltonianbull Voltage on gate directly applies to the channelbull 20A of oxide and varying well widthsbull Wave functions are strongly excluded form the oxidebull Lattice spacing and dimension varies with materialbull (100) surfacebull Inversion charge density was a constant at 1e13cm2
insulator
insulator
channelsource
drain
X
Z
Vg
0
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
13
TI Fellows Forum
PROCEDUREPROCEDUREbull 1-D Schrodinger Poisson
Solver
U(r) n(z)
[Hz+U]m= mm
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
14
TI Fellows Forum
ProcedureProcedure
bull From Schroumldinger part of the solution we get the eigen values and eigen functions
bull We can then calculate the electron density n(z)
bull Using the Poissons equation we then solve for the self consistent potential and use this new potential in the Schroumldingers equation and thus solve self consistently
bull For the Hamiltonian the mass to be used is the out of plane effective mass and for the density of states expression use the DOS mass
15
TI Fellows Forum
ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
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ResultsResults
SiGeGaAsInSb
Ninv=1e13cm2
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TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
16
TI Fellows Forum
CONCLUSIONSCONCLUSIONS
bull As the mass reduces the quantum confinement effects are more significant and peaking of the charge concentration takes place deeper in the substrate
bull This means that the effective gate capacitance is smaller in Ge and GaAs as compared to silicon
bull Also there is better gate control of channel in silicon devices as compared to GaAs and Ge
bull Higher voltages are required by III-V materials to reach the same inversion charge density when compared to silicon
bull Lower transconductance in materials with lower mass
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
17
TI Fellows Forum
Existing ResultsExisting Results
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
18
TI Fellows Forum
Current ResearchCurrent Research
Germaniumbull The main supporters of Germanium are
Sematech IBM Umicore and Soitech A lot of research is also being carried out in this field by IMEC in partnership with Umicore and Soitech
GaAsbull Intel is one of the main supporters of GaAs bull Quintec researches in this area
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
19
TI Fellows Forum
References and AcknowledgementReferences and Acknowledgementbull Quantum Transport ndash Atom to transistorSupriyo Dutta Cambridge university pressbull Physics of Strain Effects in Semiconductors and MOSFETsY Sun S E Thompson and T Nishida awaiting publicationbull Gallium Arsenide ndashGaAs as a semiconductor its turbulent past shaky present and
promising but distant futureAseem Srivastava IEEE 1989bull httpwwwedncomarticleCA6314526htmlref=nbrabull httpwwwinvestorrelationsumicorecomenpressReleases2003
germanium_Epdfbull Fundamentals of modern Vlsi devicesTaur and Ningbull httpmemscaltecheducoursesEE4020Web20Fileseffective20mass
20explanationpdfbull Indium Phosphide and related materials 2005 International conference onbull wwwintelcombull ftpdownloadintelcomresearchsiliconGordon_Moore_ISSCC_021003pdfbull wwwcompoundsemiconductornetarticlesnews101251
20
Thank youThank youQuestions
21
TI Fellows Forum
20
Thank youThank youQuestions
21
TI Fellows Forum
21
TI Fellows Forum
