Optimized Selective-Area p-Type Diffusion for the Back-Illuminated Planar InGaAs/InP Avalanche Photodiodes by a Single Diffusion Process

Herein, an alternative approach of selective-area zinc diffusion technique by single rapid thermal diffusion (RTD) using a Zn3P2/Zn/SiO2 multilayer structure is proposed to realize p-type doping in the InP cap so as to fabricate planar InGaAs/InP avalanche photodiodes (APDs). Through the optimization of selective-area zinc diffusion in the InP cap, a low dark current, high responsivity, fast transient response, and high reliability near-infrared back-illuminated planar InGaAs/InP APD is obtained, which demonstrates a simple and efficient method for the development of high-performance planar InGaAs/InP APD focal plane arrays.