Silicon Photomultiplier Device Architecture with Dark Current Improved to the Ultimate Physical Limit

This paper describes a silicon photomultiplier device architecture achieving the ultimate physical limit of the dark count level. Two different structures are compared and the resulting dark count levels as a function of temperature and applied overvoltage are modelled by a 2D drift-diffusion device simulator. In the best structure, the concentration of minority carriers (electrons) approaching the depletion region from the anode side is below the concentration of holes approaching the depletion region from the cathode side. An improvement in the dark count level of a factor 50 is experimentally found, close to the ultimate physical limit.