Photo-response edge effect of back-illuminated planar InGaAs/InP focal plane arrays

Abstract

Based on planer process with sealed-ampoule diffusion method, back-illuminated 32 × 32 pixels planar InGaAs/InP detectors were fabricated by using N-InP/i-In0.53Ga0.47As/N-InP double-heterostructure epitaxial materials and wire-bonded to readout integrated circuit (ROIC) to form near infrared focal plane arrays (FPAs). The photo-response edge effect of the detector was further analyzed with the aid of laser beam induced current (LBIC) technique under different laser powers. Moreover, the photoelectric characteristics including I-V characteristics and temperature-dependent spectral response were also investigated. The results indicate that the photo-response edge effect is caused by the lateral collection effect of photogenerated carriers, so the edge pixels could absorb more carriers generated in the surrounding undoped Zn-diffused regions. And then the method to optimize the detector design and performance was given. Otherwise, the main component of the forward current is diffusion current at room temperature. The density of dark current and R0A are 7.4 nA cm−2 (@−100 mV) and 4.7 × 106 Ωcm2 respectively. The average peak detectivity is 1.0 × 1012 cm Hz1/2/W.