Innovative back-side illuminated SiPMs development: first results from the IBIS project

Abstract Recent advancements in front-side illuminated Silicon photomultipliers (SiPMs) have led to significant improvements in fill factor and photon detection efficiency. However, achieving further enhancements is challenging without substantial modifications to the microcell architecture. To address these limitations, a novel approach based on back-side illuminated SiPMs has been introduced, offering the potential for a 100% fill factor even with small microcell dimensions. This work presents the characterization and performance evaluation of the first prototypes of back-side illuminated Silicon photomultipliers developed for high-energy physics and advanced imaging applications. The activity is done in the framework of the IBIS project, featuring a collaboration between INFN and FBK.