KETEK's SiPM data sheets detail key performance parameters of their silicon photomultipliers - a key parameter is the Breakdown Voltage which is explained in more detail below.
SiPMs operate above breakdown voltage and exhibit a sudden rise in Dark Current at the breakdown voltage.
Below breakdown the current density is typically 1 nA/cm² and is dominated by carrier diffusion and generation.
Above breakdown current density is in the range of 10µA-1mAcm². This dark current is caused by thermally generated electrons, which trigger the discharge of microcells.
SiPMs have a positive temperature coefficient of the breakdown voltage. The value of this temperature coefficient depends in a first approximation on the depth of the avalanche zone and is typically 22mV/°C for KETEK WB-Series SiPMs.
KETEK's tightly controlled CMOS wafer fabrication processes result in excellent breakdown voltage uniformity with only a small spread of ±300mV. It is therefore possible to power all SiPMs using the same bias voltage whilst also achieving uniform Gain - since Gain is a function of the of the overvoltage (voltage above breakdown). This attribute is equally beneficial regardless of whether a customer is using many individual SiPMs or large arrays as it allows a single bias voltage, reduced system design complexity and reduced cost.