High-sensitivity, wide-dynamic-range avalanche photodiode pixel design for large-scale imaging arrays

Abstract

We present a detailed design study for a novel solid-state focal plane array of silicon avalanche photodiodes (APDs), with each detector in the array capable of operating with wide dynamic range in linear or Geiger-mode. The detector array is based on back-illuminated, crystallographically etched, (100) epitaxial silicon on R-plane sapphire substrates using 27 µm pixels, although other sizes could be supported as well. Analysis of the APD pixel design, which includes the photoelectron noise, dark current noise, and electronic circuit noise, shows the capability of imaging with a signal-to-noise ratio greater than 7 at −30 °C and ultralow illuminance of 10−4 lux. The detector array design will enable large focal planes, capable of imaging with high sensitivity and high speed, over a wide range of natural illumination conditions from direct sunlight to a cloudy moonless night.