Aspects of chip and cell size of silicon photomultipliers

Requirements like device miniaturization, insensitivity to magnetic field and cost aspects in the field of low level light detection will lead to a replacement of the conventional photomultiplier tube by Silicon Photomultiplier (SiPM) for several applications in case the photon detection efficiency will be comparably higher at the same price level. This novel solid-state sensor consists of an array of parallel connected avalanche photodiodes operated in limited Geiger-mode. The triggered cells are recovered by an upstream connected quenching resistor. The main characteristics are gain, noise, photon detection efficiency (PDE), dynamic range and time resolution. To meet the requirements of various potential applications, SiPMs need to be available with several micro pixel sizes and total active areas. For this reason KETEK produces devices with microcell pitches from 15 mu m up to 100 mu m and total active sensor areas from 1.0 x 1.0 mm(2) up to 6.0 mm x 6.0 mm(2). The effects of this scaling on the SiPM device parameters are discussed.