Ultra-low noise and exceptional uniformity of SensL C-series SiPM sensors

Abstract

SensL C-Series Silicon Photomultiplier (SiPM) sensors are fabricated in a high-volume CMOS foundry to a custom SensL process, and packaged as a reflow solderable surface mount device. Advances in SiPM production have resulted in significant improvement in PDE, dark current as well as tighter breakdown voltage uniformity for the C-Series SiPM sensors. The SiPM are fabricated with a shallow P-on-N junction optimized for the detection of shorter wavelength photons, with a peak PDE of 41% at 420nm and excellent sensitivity extending to wavelengths <300nm. The dark currents have been reduced through the reduction of damage during semiconductor processing and an order of magnitude reduction has been achieved. The breakdown voltage variation has been improved through process optimization to minimize variations. With these process improvements typical dark count rates of ~30kHz/mm2 are achieved simultaneously with breakdown voltage uniformity of ±213mV demonstrated. In addition, application specific measurements of CRT (Coincidence Resolving Time) that are relevant to PET (positron emission tomography) will be shown to be 210ps at 7.5V overvoltage. In addition to device characterization work, this paper will address the wafer-level fabrication and testing, package level testing required by high volume SiPM sensor applications.