The characteristics of photo-CVD SiO2 and its application on SiC MIS UV photodetectors

SiO2 layers were deposited onto SiC by photo-chemical vapor deposition (photo-CVD) using deuterium (D2) lamp as the excitation source. For the photo-SiO2 deposited 500 °C, interface state density (Dit) was estimated to be 5.66×1011 cm−2 eV−1. With an applied electric field of 4 MV cm−1, it was found that the leakage current was only 3.15×10−8 A cm−2 for the photo-CVD SiO2 layer prepared at 500 °C. It was also found that photo-SiO2 could effectively suppress dark current of SiC-based photodetectors (PDs). It was found that we could reduce dark current of SiC-based PDs by about three orders of magnitude by the insertion of a 5 nm-thick photo-CVD SiO2 film in between Indium-tin-oxide (ITO) contact and the underneath SiC. Photocurrent to dark current ratio of ITO/SiO2/SiC MIS PDs was also found to be much larger than that of conventional ITO/SiC Schottky barrier PDs.