Electrical Characterization of SiPM as a Function of Test Frequency and Temperature

TL;DR

This study characterizes silicon photomultipliers (SiPMs) electrically across various frequencies and temperatures, providing insights into their behavior for high-energy and medical physics applications.

Contribution

It presents detailed electrical measurements of SiPMs, including capacitance and leakage currents, and introduces a model to explain frequency-dependent capacitance behavior.

Findings

Capacitance varies with frequency and temperature.

Leakage current threshold voltage depends on temperature.

An electrical model accurately reproduces frequency-dependent capacitance.

Abstract

Silicon Photomultipliers (SiPM) represent a promising alternative to classical photomultipliers, for instance, for the detection of photons in high energy physics and medical physics. In the present work, electrical characterizations of test devices - manufactured by ST Microelectronics - are presented. SiPMs with an area of 3.5x3.5 micron^2 and a cell pitch of 54 micron were manufactured as arrays of 64x64 cells and exhibiting a fill factor of 31%. The capacitance of SiPMs was measured as a function of reverse bias voltage at frequencies ranging from from 20 Hz up to 1 MHz and temperatures from 300 K down to 85 K. While leakage currents were measured at temperatures from 400 K down to 85 K. Thus, the threshold voltage - i.e., voltage corresponding to that at which the multiplication regime for the leakage current begins - could be determined as a function of temperature. Finally, an electrical model suited to reproduce the dependence of the frequency dependence of capacitance is presented.