Using of laser ablation technique in the processing technology of GaN/SiC based MEMS for extreme conditions

In order to improve the stability, sensitivity or efficiency of AlGaN/GaN based sensors employing high electron mobility transistors (HEMTs), Schottky diodes and/or resistors they should be integrated into micro-electro-mechanical-systems (MEMS). The creation of appropriate diaphragms and/or cantilevers is necessary for the verification of sensing properties of such MEMS sensors. In this paper, we present possible approaches to improve the fabrication of micromechanic structures in bulk SiC substrates with epitaxial AlGaN/GaN heterostructures using femtosecond laser ablation to fabricate SiC diaphragms. The objective of this work is also to point at the backside damaging effects and to find an optimal method for its elimination or suppression.