Semiconductor photo-detector having a two-stepped impurity profile.

摘要

A semiconductor photo-detector having a two-stepped impurity profile comprises a semiconductor substrate (10), a light absorption layer (14) of a first conductivity type formed on a semiconductor substrate, a multiplication layer (18) of a first conductivity type formed on the light dbsorption layer to multiply a photocurrent, a semiconductor region (22) of a second conductivity type formed on the multiplication layer and constituting an abrupt pn junction with the multiplication layer, and a guard ring area (38) of a second conductivity type formed around a periphery of the semiconductor region, whereby the carrier concentration profile of the guard ring region is sharp at its surface and flat below that surface.