skip to main content

Title: Depth dependence of defect density and stress in GaN grown on SiC

We report high resolution x-ray diffraction studies of the relaxation of elastic strain in GaN grown on SiC(0001). The GaN layers were grown with thickness ranging from 0.29 to 30 {mu}m. High level of residual elastic strain was found in thin (0.29 to 0.73 {mu}m thick) GaN layers. This correlates with low density of threading screw dislocations of 1-2x10{sup 7} cm{sup -2}, observed in a surface layer formed over a defective nucleation layer. Stress was found to be very close to what is expected from thermal expansion mismatch between the GaN and SiC. A model based on generation and diffusion of point defects accounts for these observations.
Authors:
; ; ; ;  [1] ;  [2] ;  [2] ;  [2]
  1. Department of Electrical and Computer Engineering, University of Delaware, 140 Evans Hall, Newark, Delaware 19716 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20787719
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 98; Journal Issue: 12; Other Information: DOI: 10.1063/1.2141651; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; GALLIUM NITRIDES; LAYERS; NUCLEATION; POINT DEFECTS; SCREW DISLOCATIONS; SEMICONDUCTOR MATERIALS; SILICON CARBIDES; STRAINS; STRESS RELAXATION; THERMAL EXPANSION; THICKNESS; X-RAY DIFFRACTION