Study on Improvement of Dark Count Rate for Silicon Photomultiplier

The dark count rate (DCR) is a major factor limiting the application of silicon photomultiplier(SiPM). It is widely believed that one of the major origins of DCR is generation effects from Shockley-Read-Hall (SRH) defects near the depletion region, on which plasma induced damage (PID) of the interfacial regions including STI, DTI and photodiode surface plays a substantial role. Normally for backside illuminated (BSI) SiPM, high-k films induced hole accumulation at the interface of DTI-Si is employed to reduce DCR, however, this option is not available for front-side illuminated (FSI) SiPM due to contamination concerns. Therefore, systematic studies are conducted in this paper for improving DCR by process optimization, finally the DCR is improved significantly.