CMOS SPADs have been irradiated with X-ray doses up to 1 Mrad(SiO2) and neutron fluences of 1 MeV equivalent neutrons up to 1011 cm-2. In particular, in SPADs exposed to neutrons, the distribution of the dark count rate increase was found to be directly related with the distribution of the energy deposited in the active region of the device, in agreement with the NIEL (non-ionizing energy loss) hypothesis. The study of radiation damage in SPADs is of paramount importance to anticipate the time to failure of a SPAD detector and may therefore be used as a tool to optimize the radiation tolerant design of the system.
Electronic Instrumentation Laboratory
UNIVERSITY OF PAVIA
