Study of the breakdown voltage of SiPMs

TL;DR

This study investigates the breakdown voltages of SiPMs with various pixel sizes, comparing different measurement methods and analyzing their dependence on pixel size, providing insights into their breakdown behavior.

Contribution

It introduces a comprehensive analysis of SiPM breakdown voltages using multiple measurement techniques across different pixel sizes, revealing their relationships and dependencies.

Findings

$V_I$ and $V_{PD}$ are equal and independent of pixel size.

$V_G$ depends on pixel size, decreasing as pixel size increases.

The difference $V_I - V_G$ varies with pixel size, approaching zero for larger pixels.

Abstract

The breakdown behaviour of SiPMs (Silicon PhotoMultiplier) with pixel sizes of 15$\times $15, 25$\times $25, 50$\times $50, and 100$\times $100 $\mu $m$^2$, manufactured by KETEK, has been investigated. From the current-voltage characteristics measured with and without illumination by LED light of 470 nm wavelength, the current-breakdown voltage, $V_I$, and from linear fits of the voltage dependence of the SiPM gain, measured by recording pulse-area spectra, the gain-breakdown voltage, $V_G$, have been obtained. The voltage dependence of the Geiger-breakdown probability was determined from the fraction of zero photoelectron events with LED illumination. By comparing the results to a model calculation, the photodetection-breakdown voltage, $V_{PD}$, has been determined. Within experimental uncertainties, $V_I$ and $V_{PD}$ are equal and independent of pixel size. For $V_G$, a dependence on pixel size is observed. The difference $V_I - V_G$ is about 1 V for the SiPM with 15 $\mu $m pixels, decreases with pixel size and is compatible with zero for the SiPM with 100 $\mu $m pixels.