Direct Bonding of 4H-SiC and SOI Wafers for Radiation-Hardened Image Sensors

Abstract

4H-SiC and SOI substrates were bonded by SiO2-SiO2 direct bonding method with diluted HF solution (0.5 wt.%). After the bonding process, the handle layer and the BOX layer of the SOI substrate were etched by TMAH solution, and finally the silicon active layer with a thickness of 1.5 μm was remained on the 4H-SiC substrate. Using this silicon layer, Si photodiodes on 4H-SiC for the radiation hardened image sensors were fabricated and demonstrated.