Avalanche photodiode array integrated with etched silicon divider

Abstract

An avalanche photodiode array comprising a plurality of photosensitive regions in a light sensitive body with each photosensitive region having a semiconductor junction. Between said photosensitive regions, there are a plurality of low response regions separating the photosensitive regions. A plurality of wedged shaped regions having a reflective coating on their surface are placed on the light sensitive body to cover the low response regions and to reflect incident light rays towards a photosensitive region; such incident light rays typically arriving at the photosensitive regions at angles of grazing incidence. Back reflector regions having a reflective coating on their surface are positioned about the periphery of the light entry surface to reflect light incident thereon to a photosensitive region. Placed upon the surface of the photosensitive elements is an antireflection coating comprised of a low loss material having a high index of refraction such that light rays incident on the photosensitive element at an angle of grazing incidence may deliver substantially all of their energy either to the photosensitive region so as to be detected or to the reflected rays to be reflected by the back reflector and subsequently detected, rather than having their energy dissipated by heat loss in a more lossy antireflection coating. The index of refraction of the anti-reflecting coating is approximately equal to the square root of the index of refraction of the material from which a light sensitive body is comprised.