Digital SiPMs and SPAD arrays: available technologies and implementation challenges for large arrays

CMOS-based individual SPAD detectors and arrays have seen a host of applications being explored and industrialised in the past years, relying on their single-photon detection capability, combined with excellent photon-timing precision and noiseless read-out (in the digital flavour). SPADs are available in most standard CMOS technologies, with sensitivities spanning the entire spectrum, from NUV to NIR.Digital SiPMs are one of the array flavours, where the intrinsically digital nature of the SPAD response is preserved and exploited as close as possible to the SPAD itself, without necessarily reaching the granularity of true imagers. We will have a look at some of the recent commercial developments, technology trends and general manufacturing options, with emphasis on manufacturing bottlenecks and opportunities. This will be complemented by a closer look at tiling and tiling-enabling technologies, such as TSVs, which are of particular importance to the high-energy physics and nuclear science community in the large sense (e.g. including Positron Emission Tomography). The corresponding applications do indeed often emphasize large-area implementations coupled to high detection efficiency and fill factor.