AlN/GaN/spphire as promising structure for wireless, batteryless and packageless acoustic wave sensors for high temperature applications

摘要

Waveguiding layer acoustic waves (WLAW) technology is considered as a packageless solution for extreme miniaturization of acoustic wave devices. WLAW solution is also original and suitable for high-temperature applications. Indeed, the achievement of a stable high-temperature packaging still constitutes a technological lock, in particular regarding sealing performance. In this context, we consider AlN/GaN/Sapphire as a promising WLAW structure for high-temperature applications. Indeed, the high-temperature stability of these three materials was previously demonstrated. However, in order to develop fully operational WLAW sensors based on this layered structure, it is necessary to have a better knowledge of the behaviour of each constitutive material with respect to the temperature. Consequently, the aim of this work is to experimentally validate GaN and AlN elastic constants sets in a large temperature range, which is a prerequisite to make the design of WLAW sensors according to the targeted performance.