High Temperature Measurement of Elastic Moduli of (0001) Gallium Nitride

Abstract

This paper aims to review the consistency of existing GaN stiffness data and measure the high temperature elastic moduli of free-standing (0001) GaN. Dynamic mechanical thermal analysis (DMTA) and impact excitation were used to determine the E₃₃ elastic modulus at room temperature and at temperatures up to 550°C. At room temperature, E₃₃ ranged from 304 GPa to 279 GPa depending on the specific sample and measurement method. Using DMTA and a calibration with silicon, the elastic modulus decreased by 2.17% between 100°C and 500°C, in close agreement with the literature. By testing samples cut at a range of crystal orientations the isotropy of the stiffness in the (0001) plane was confirmed.

Keywords:

• Elastic modulus
• gallium nitride
• dynamic mechanical thermal analysis

Acknowledgments

The research leading to these results has received funding from the European Community's Seventh Framework Programme FP7/2007-2011 under grant agreement n°214610, project MORGaN. This publication reflects only the author's views and that the Community is not liable for any use that may be made of the information contained therein.