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
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?
Typical SiC Wafers SiC FWHM
SiC XRD correlation with GaN XRD
SiC/GaN FWHM Relationship GaN FWHM not influenced by SiC
GaN Thickness Data
AlN Buffer Layer Changes
AlN vs AlGaN Buffer Layers
PL maps vs. X-ray maps
Electrical results – Mobility vs Resistivity
Electrical results – Mobility vs Bulk Carrier Concentration
Electrical results – Mobility
Electrical results – Resistivity
Electrical results – Carrier Concentration
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