InGaN/GaN Multi-Quantum Well Metal-Insulator Semiconductor Photodetectors with Photo-CVD SiO₂ Layers

Abstract

InGaN/GaN multiple-quantum well (MQW) structure was epitaxial growth by metal-organic chemical vapor deposition (MOCVD). Their MIS photodiodes with SiO 2 interlayer were fabricated successfully using photochemical vapor deposition. The normal undoped-GaN metal-semiconductor-metal (MSM) potodiodes were also prepared to compare with them. It was found that the minimum dark current of InGaN/GaN MQW photodiodes was 4.2×10 -13 A with 88 nm-thick SiO 2 layer under 5 V reverse bias voltage. Furthermore, it was found that we can significantly reduce the dark current of this photodiodes by inserting a thin SiO 2 interlayer in between metal electrode and the underneath InGaN/GaN MQW. With a 53 nm-thick SiO 2 interlayer, it was also found that we could achieve a high 1.53×10 3 photo current to dark current contrast.