Experimental and TCAD Study of Breakdown Voltage Temperature Behavior in $n^{+}/p$ SiPMs

In this paper, the breakdown voltage in avalanche photodiodes operating in Geiger mode is investigated. In particular, the breakdown voltage dependence on the structural characteristics of n⁺/p avalanche diodes, such as implant dose and epitaxial layer thickness and doping concentration, as well as the temperature behavior are analyzed. The study includes both experimental data and numerical simulations. The first are acquired in a controlled temperature environment on samples featuring different electrical structures. Simulations are performed both at the technological process as well as at the electrical level using a commercial TCAD software. Agreement between experiments and numerical analysis is found to be quite good and first hints on how to improve the breakdown voltage uniformity and temperature dependence are given. Moreover, with the aid of TCAD simulations, the potential sources of device breakdown voltage fluctuations related to both device process variability and the properties of the starting silicon wafers are investigated.