Silicon based single-photon avalanche diode technology for low-light and high-speed applications

This chapter describes the functional principles of single-photon counting in silicon achieved by using single-photon counting avalanche diode (SPAD) technology. It explains the different readout modes of single SPADs on the one side, and of arrays of SPADs forming silicon photomultipliers (SiPM) with analog output, SiPMs with a digital output, or SPAD arrays that can be read out in form of frames that form SPAD-based imagers, on the other. This silicon-based technology is compared to traditionally used photomultiplier tube, multichannel plate, or image intensifier technologies in applications requiring near single-photon counting and time responses in a nanosecond or subnanosecond regions. This chapter also discusses the fabrication issues of SPAD devices as well as figures of merit used for their characterization. Finally, the chapter explains how SPAD arrays are used in time-of-flight-based ranging and/or 3D imaging applications.