Optical and Noise Performance of CMOS Solid-State Photomultipliers

摘要

Solid-state photomultipliers (SSPM) are photodetectors composed of avalanche photodiode pixel arrays operating in Geiger mode (biased above diode breakdown voltage). They are built using CMOS technology and can be used in a variety of applications in high energy and nuclear physics, medical imaging and homeland security related areas. The high gain and low cost associated with the SSPM makes it an attractive alternative to existing photodetectors such as the photomultiplier tube (PMT). The capability of integrating CMOS on-chip readout circuitry on the same substrate as the SSPM also provides a compact and low-power-consumption solution to photodetector applications with stringent area and power requirements. The optical performance of the SSPM, specifically the detection and quantum efficiencies, can depend on the geometry and the doping profile associated with each photodiode pixel. The noise associated with the SSPM not only includes dark noise from each pixel, but also consists of excess noise terms due to after pulsing and inter-pixel cross talk. The magnitude of the excess noise terms can depend on biasing conditions, temperature, as well as pixel and inter-pixel dimensions. We present the optical and noise performance of SSPMs fabricated in a conventional CMOS process, and demonstrate the dependence of the SSPM performance on pixel/inter-pixel geometry, doping profile, temperature, as well as bias conditions. The continuing development of CMOS SSPM technology demonstrated here shows that low cost and high performance solid state photodetectors are viable solutions for many existing and future optical detection applications.