Resonant-cavity-enhanced 4H-SiC thin film MSM UV photodetectors on SiO₂/Si substrates

Abstract

Heterogeneous integration of 4H-SiC film with Si substrate can produce UV photodetectors (PD) with higher performance and easier integration with silicon CMOS circuits than homogenous epitaxy of 4H-SiC on SiC substrates. In this study, 1.2 µm thick high-quality single crystalline 4H-SiC thin films were successfully bonded with a SiO2/Si (100) substrates using the Smart-Cut technique, achieving bubble-free bonding interfaces and 6.03 MPa bonding strength. Ultraviolet (UV) PDs of MSM type with a resonant cavity structure were fabricated for the first time using the heterogenous film sample. The device exhibits a low dark current of 1.6×10-13 A in reverse bias of 20 V and a maximum specific detectivity of about 5.2×1012 Jones at 280 nm, which is significant for a device with a resonance-enhanced structure. These results demonstrate a promising approach for the fabrication of SiC devices with silicon CMOS circuits.