Patent ID: 7214971

Claim:
A semiconductor light-receiving device comprising: a semi-insulating substrate having a front side including upper, middle and lower regions, the lower region being connected to the upper and middle regions; a p-type first semiconductor layer provided on the lower region, the first semiconductor layer having a top surface including a first portion adjoining and substantially on a level with the middle region, and a second portion on a level with or above the first portion; an n-type second semiconductor layer provided on the first semiconductor layer, the second semiconductor layer having a top surface including a third portion adjoining and substantially on a level with the upper region, and a bottom surface; a first electrode covering at least part of a boundary between the middle region and the first portion, the first electrode being electrically in contact with the first semiconductor layer; and a second electrode covering at least part of a boundary between the upper region and the third portion, the second electrode being electrically in contact with the second semiconductor layer, wherein the semi-insulating substrate is made of semi-insulating GaAs; wherein the first semiconductor layer is made of p-type GaAs; and wherein the second semiconductor layer is made of n-type GaAs.