Patent ID: 6791124
Filing Date: 2004-09-14
Classification: H01L,Y02E

Abstract:
A sequential mesa type avalanche photodiode comprising:an n-type semiconductor substrate; and a sequential mesa portion formed on an upper part of the n-type semiconductor substrate, said sequential mesa portion comprising a plurality of semiconductor layers which include: an n-type light absorbing layer, an n-type electric field relaxation layer formed on an upper part of the n-type light absorbing layer, and a p-type multiplying layer formed on the n-type electric field relaxation layer and laminated by epitaxial growth, wherein the p-type multiplying layer and the n-type electric field relaxation layer form a pn junction, wherein a carrier density of the n-type electric field relaxation layer is larger than a carrier density of the p-type multiplying layer, and wherein when light is incident from the n-type semiconductor substrate toward the n-type light absorbing layer, electrons and positive holes are generated in the sequential mesa portion and positive holes are a main carrier, and there is a single-peaked characteristic in which light-receiving current based on movement of the electrons and the positive holes is larger at a central portion of the sequential mesa portion than at a peripheral portion of the sequential mesa portion.