Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
SiC influence on x-ray measurements of GaN films compared with
photoluminescence and electrical data
E.A. Preble, Z. Reitmeier, S. Einfeldt, R.F. DavisNorth Carolina State University
D.S. Katzer, H DietrichNaval Research Labs
Ulrich SchwartzUniversität Regensburg
February 12, 2002
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
Topics of discussion
• Background– SiC wafer variability– SiC influence on GaN x-ray data
• Wafer mapping as a solution to SiC influence– Extraction of reliable and repeatable x-ray data
• Do x-ray map results correlate to PL and electrical results?
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
Typical SiC Wafers
SiC FWHM
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
SiC XRD correlation with GaN XRD
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
SiC/GaN FWHM Relationship
GaN FWHM not
influenced by SiC
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
GaN Thickness Data
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
AlN Buffer Layer Changes
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
AlN vs AlGaN Buffer Layers
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
PL maps vs. X-ray maps
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
Electrical results – Mobility vs Resistivity
Mobility vs. Resistivity
300
320
340
360
380
400
420
3.5E-02 4.5E-02 5.5E-02 6.5E-02 7.5E-02
Resistivity (ohm/cm^2)
Mo
bilt
iy (
cm
^2
/V.s
)
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
Electrical results – Mobility vs Bulk Carrier Concentration
Mobility vs. Bulk Carrier Concentration
300
320
340
360
380
400
420
2.7E+17 2.9E+17 3.1E+17 3.3E+17 3.5E+17 3.7E+17
Carrier Concentration (cm^-3)
Mo
bili
ty (
cm
^2
/V.s
)
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
Electrical results – Mobility
Mobility vs. FWHM
300
320
340
360
380
400
420
250 350 450 550 650
GaN (00.2) FWHM (arcsec)
Mo
bili
ty (
cm
^2
/V.s
)
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
Electrical results – ResistivityResistivity vs. FWHM
3.5E-02
4.0E-02
4.5E-02
5.0E-02
5.5E-02
6.0E-02
6.5E-02
7.0E-02
7.5E-02
250 350 450 550 650
GaN (00.2) FWHM (arcsec)
Re
sis
tiv
ity
(o
hm
.cm
)
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
Electrical results – Carrier Concentration
Bulk Carrier Concentration vs. FWHM
2.7E+17
2.9E+17
3.1E+17
3.3E+17
3.5E+17
3.7E+17
250 350 450 550 650
GaN (00.2) FWHM (arcsec)
Ca
rrie
r C
on
ce
ntr
ati
on
(c
m^
-3)
Compact Power Supplies Based on Heterojunction Switching in Wide Band Gap Semiconductors
NC STATE UNIVERSITY UCSB
Why isn’t there a correlation?
• XRD vs PL– X-ray measurements are bulk measurements– PL measurements are more localized– Correlations are not found because of scale difference
• XRD vs Electrical Data– Both measurements are large area– Electrical results are not sensitive to domain tilting that is
observed via XRD– This x-ray technique is not useful in prediction of electrical
results
