SiC Wafer Bonding and Deep Reactive Ion Etching Towards High-Aspect Ratio SiC MEMS Fabrication

• Main Authors: Luna, Lunet E, Hobart, Karl D., Tadjer, Marko J, Myers-Ward, Rachael L., Anderson, Travis J., Kub, Francis J
• Format: Conference Proceeding
• Language: English
• ISSN: 1938-5862; 1938-6737; 1938-6737; 1938-5862
• DOI: 10.1149/08605.0105ecst

High-yield wafer bonding with minimal bonding imperfections and high-aspect etch process of 4H-SiC/SiO2/4H-SiC stacks is presented. The top 4H-SiC layer is thinned, patterned, etched, and is then ready to be released to form the MEMS device layer. An anti-bosch process is used to etch high aspect ratio trenches within the 4H-SiC device layer in the presence of buried oxide; the oxide serves both as a sacrificial layer and as an etch stop. The etch yields an aspect ratio of 10.5 (42.9 μm etch depth : 4.1 μm mask opening) within the 4H-SiC device layer. The handle wafer is 4H-SiC, as opposed to Si, which allows for all SiC-based MEMS devices for high shock resistant and temperature applications.