1. SiC influence on x-ray measurements of GaN films compared with photoluminescence and electrical data
E.A. Preble, Z. Reitmeier, S. Einfeldt, R.F. Davis
North Carolina State University
D.S. Katzer, H Dietrich
Naval Research Labs
Ulrich Schwartz
Universität Regensburg
February 12, 2002

2. 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?

3. Typical SiC Wafers
SiC FWHM

4. SiC XRD correlation with GaN XRD

5. SiC/GaN FWHM Relationship
GaN FWHM not
influenced by SiC

6. GaN Thickness Data

7. AlN Buffer Layer Changes

8. AlN vs AlGaN Buffer Layers

9. PL maps vs. X-ray maps

10. Electrical results – Mobility vs Resistivity

11. Electrical results – Mobility vs Bulk Carrier Concentration

12. Electrical results – Mobility

13. Electrical results – Resistivity

14. Electrical results – Carrier Concentration

15. 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