Relaxation Process of the Thermal Strain in the GaN/α-Al2O3 Heterostructure and Determination of the Intrinsic Lattice Constants of GaN Free from the Strain
- 1 October 1992
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 31 (10B), L1454
- https://doi.org/10.1143/jjap.31.l1454
Abstract
The relaxation process of the thermal strain in a GaN film due to the thermal expansion coefficient difference in the GaN(0001)/α-Al2O3(0001) heterostructure is studied by varying the film thickness of GaN in a wide range from 1 to 1200 µm. The lattice constant c has a large value of 5.191 Å at a film thickness less than a few microns, while it decreases to about 150 µm, and becomes constant above 150 µm, indicating that the strain is almost completely relaxed. The intrinsic lattice constants of wurtzite GaN free from the strain, a 0 and c 0, are determined to be 3.1892±0.0009 and 5.1850±0.0005 Å, respectively.Keywords
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