Update to Radiation Effects in GaN
Leif Scheick Jet Propulsion Laboratory, California Institute of Technology,
Pasadena, Ca This Research Was Carried Out In Part by the Jet Propulsion Laboratory, California Institute of Technology, Under Contract With the National Aeronautics and Space
Administration Under the NASA Electronic Parts and Packaging Program (Code AE). Other data was collected from NASA flight projects.
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
Previous body of knowledge on GaN
• Current silicon power solutions are at their innate limits for space applications – Silicon devices are at
efficiency limit – Best hi-rel devices are less
then ~400 V drain-to-source • GaN devices are becoming
available – Reliability effects are a
concern – Gate stress is limited (abs max
of Vgs +6, -5 V) – Thermal effects and aging are
under study at GRC
Dielectric
GaN- - - - - - - - - - - - - - -
Si
AlGaN Electron Generating Layer
DGS- - - -
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
Previous body of knowledge on GaN • SEEs in GaN have been
observed • Used the NEPP guideline:
The Test Guideline for Single Event Gate Rupture (SEGR) of Power MOSFETs [JPL Publication 08-10 2/08] – No post irradiation stress tests
between – Testing at angle required
0 500 1000 1500 2000 2500Elapsed time [AU]
10-10
10-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
Cur
rent
(Id)
[A]
0
40
80
120
160
200
Dra
in-to
-sou
rce
Volta
ge (V
ds) [
V]
K7352 1569 MeV Xe EPC2012 200V/3A 0deg
0 0.4 0.8 1.2 1.6 2Gate-to-source Voltage (Vgs) [V]
10-7
10-6
10-5
10-4
10-3
10-2
10-1
Dra
in c
urre
nt (I
d) [A
]
K7359EPC20120 rad(Si)1600 rad(Si)6400 rad(Si) (SEE)
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
Previous body of knowledge on GaN
• Devices with lower voltage rating were less susceptible to dose damage
• At normal incidence, the higher LET ion does more damage – Devices irradiated at 60o
tilt showed little degradation
– Devices irradiated at 60o roll showed some degradation
• Gen2 parts were more robust than Gen1
Vds [V]
Gen 1
VSEE [V]
Gen 1
VSOA [V]
Gen 2
VSEE [V]
Gen 2
VSOA [V]
40 40 30 40 30
100 40 30 60 45
200 40 30 80 60
VSEE for GaN for all Vgs<Vth
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
Spreading resistance measurement
5
EPC1012 EPC2012
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
Current investigations
• Proton damage – Upper limit for damage – SEE from spallation reactions
• Tungsten in device structure will generate secondaries in that may replicate SEE effects
• Recommended testing/assurance methods – 1080 test circuit – Prioritization of test matrix – Ion conditions
• Failure mechanism identification – Failures manifesting in drain-to-source leakage have been
seen • Role of isolation oxide under scrutiny
– Failures in gate-to-source leakage have been seen • EPC1012 and EPC2012 are the most sensitive and
therefore the best candidates
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
PROTON EFFECTS
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
Proton testing results
8
-1 0 1 2 3Gate-to-source Voltage (Vgs) [V]
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
Dra
in c
urre
nt (I
d) [A
]
A4760EPC2012
0 rad(Si)3600 rad(Si)
0 0.4 0.8 1.2 1.6 2Gate-to-source Voltage (Vgs) [V]
10-7
10-6
10-5
10-4
10-3
10-2
10-1
Dra
in c
urre
nt (I
d) [A
]
K7353EPC20120 rad(Si)800 rad(Si)1600 rad(Si) 2400 rad(Si)3200 rad(Si) (SEE)4000 rad(Si)4800 rad(Si)
Proton damage Xenon damage
No SEE from protons.
-1 0 1 2 3Gate-to-source Voltage (Vgs) [V]
10-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
Dra
in c
urre
nt (I
d) [A
]
A4760EPC2012
0 rad(Si)0.5 Mrad(Si)1 Mrad(Si)
Dielectric
GaN- - - - - - - - - - - - - - -
Si
AlGaN Electron Generating Layer
DGS- - - -
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
BEST TEST METHODS
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
Effect of 1080 test circuit
0 400 800 1200
1E-014
1E-013
1E-012
1E-011
1E-010
1E-009
1E-008
1E-007
1E-006
1E-005
0.0001
0.001
0.01
-50
0
50
100
150
200
k7656 100 V Xe Vgs=0VGate current [A]Drain current [A]Drain voltage [V]
0 100 200 300 400 500
1E-013
1E-012
1E-011
1E-010
1E-009
1E-008
1E-007
1E-006
1E-005
0.0001
0.001
0.01
0
40
80
120
160
200
k7654 100 Xe Vgs=0VGate current [A]Drain current [A]Drain voltage [V]
C=10 uF
C=100 uF 0 200 400 600 800
1E-009
1E-008
1E-007
1E-006
1E-005
0.0001
0.001
0.01
0
40
80
120
160
200
k7657 100 V Xe Vgs=0VGate current [A]Drain current [A]Drain voltage [V]
C=0 uF
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
FAILURE ANALYSIS
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
Optical and SEM of EPC2012
Circle Encompassing Damaged region
Gate
Source
Drain Source
6/19/2013
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
Closer SEM View of Drain to Source Damaged Region for EPC2012
Aluminum
Carbon
Tin/Lead
Silicon Dioxide Passivation
6/19/2013
Drain Source
To be presented at the 4th NASA Electronic Parts and Packaging (NEPP) Program Electronic Technology Workshop June 11-13, 2013, NASA GSFC, Greenbelt, MD.
Conclusion
• Proton damage – DDD and proton SEE apparently not an issue for GaN – Observed effects may be architecturally dependent
• Recommended testing/assurance methods – Stiffening capacitance is recommended for worst case
• Failure mechanism identification – Isolation oxide is the drain-to-source path – SEE mechanism under study
• Future work – Identification of the SEE mechanism with follow on
modeling • Include angle, ion-energy, and bias effects
– Gate SET and RF testing
