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