Thermo-mechanical stability of wide-bandgap semiconductors: high temperature hardness of SiC, AIN, GaN, ZnO and ZnSe

The hardness of single crystals alpha-SiC, AIN,. GaN, ZnO and ZnSe at elevated temperatures was measured by the Vickers indentation method in the temperature range 20-1400degreesC. The hardness of SiC, AIN, GaN, ZnO and ZnSe is about 25, 18, 11, 5 and 1 GPa, respectively, at room temperature. SiC, AIN and GaN show a decrease in hardness, originating in the beginning of macroscopic dislocation motion and plastic deformation, only at temperature 1200degreesC. A high thermo-mechanical stability for SiC. GaN and AIN is deduced. (C) 2001 Elsevier Science B.V. All rights reserved.