High-Density Silicon Photomultipliers: Performance and Linearity Evaluation for High Efficiency and Dynamic-Range Applications

Silicon photomultipliers (SiPM) are photodetectors that have obtained a growing attention in the last years. They have single photon sensitivity, but also a high dynamic range: the output current signal is proportional to the number of detected photons and it is possible to distinguish up to tens of photon per each light pulse. In Fondazione Bruno Kessler (Trento, Italy) we developed the so called high-density SiPMs, with narrow trenches to isolate the cells (i.e. single-photon avalanche diodes) and with high fill factor. These detectors feature high photon detection efficiency and high dynamic range. Moreover, the reduction of the cell size reduces the correlated noise (i.e. lower crosstalk between cells and lower afterpulsing probability) and it makes the single-cell response faster, increasing the maximum counting rate. These characteristics can be very important in applications like light detection and ranging, spectroscopy, and physics experiments. In this paper, we present the structure of high-density SiPMs and their performance. In particular, the photon detection efficiency, the photon number resolving capabilities, the linearity versus photon flux, and the single-photon time resolution, investigating how these parameters change with the cell pitch.