Determination of Alloy Composition and Residual Stress for AlxGa1-xN/GaN Epitaxial Films
✍ Scribed by Paduano, Q. ;Weyburne, D. ;Wang, S-Q.
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 86 KB
- Volume
- 188
- Category
- Article
- ISSN
- 0031-8965
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✦ Synopsis
The alloy composition and the residual stress in Al x Ga 1--x N on GaN epi-layers can be estimated by measuring both the a-axis and c-axis lattice constants using HRXRD. Using linear elastic theory, we derive the alloy composition of a biaxial strained layer from a simple equation relating the measured c-axis and a-axis lattice constants, the lattice constants for unstrained Al x Ga 1--x N (assuming Vegard's law), and the ratio of elastic stiffness constants. The method was used to calculate the composition and strain, as well as error estimates, for a set of Al x Ga 1--x N layers grown by MOCVD with 0.23 x 0.84.