US Patent 10446601 Photodetector

A sensor includes a first substrate including at least a first pixel. The first pixel includes an avalanche photodiode to convert incident light into electric charge and includes an anode (105) and a cathode (101). The cathode is in a well region (103) of the first substrate. The first pixel includes an isolation region (108) that isolates the well region from at least a second pixel that is adjacent to the first pixel. The first pixel includes a hole accumulation region (107a) between the isolation region and the well region. The hole accumulation region is electrically connected to the anode.