Patent ID: 11335825

Abstract:
A single-photon avalanche diode (SPAD) is disclosed. In one aspect, the SPAD comprises an inner doped region, a geometrical structure of a boundary of the inner doped region rotationally symmetric in a horizontal direction of a substrate; at least one outer doped region connected to a second terminal, the at least one outer doped region arranged to at least partially enclose the inner doped region and the outer doped region comprising dopant implantations of a different type than the inner doped region; a lowly doped depletion volume arranged to surround the inner doped region, a depth of the lowly doped depletion volume extending from the top surface of the substrate into the substrate being larger than a depth of the at least one outer doped region, and when a reverse bias is applied to an anode, an electric field peak around the inner doped region being formed to enable impact ionization and multiplication of charges.