Multi-Junction Pico-Avalanche Detector

The present relates to a multi-junction photon detector comprising a semiconductor substrate, a plurality of n+ pixels on the top surface and a p+ uniform doping implant on the backside and at least one n-doped layer on the backside, deeper in the substrate bulk than the p+ implant, such that the detector presents a first PN junction corresponding to a drift and signal induction region and comprising the pixels on the substrate, and a second PN junction corresponding to a gain region and comprising the n-doped layer disposed on the backside of the detector active area deeper in the substrate bulk. These two junctions are operated in inverse polarization. The area between them contains a PN junction in direct polarization and it is fully depleted from the free charges.