Patent ID: 7368750

Claim:
A semiconductor light-receiving device for a high-speed and large-capacity optical fiber communication system comprising: a) a semi-insulating substrate; b) a semiconductor layer of a first conduction type that is formed on the semi-insulating substrate; c) a buffer layer of the first conduction type that is formed on the semiconductor layer; d) a light absorption layer that is formed on the buffer layer and generates carriers in accordance with incident light; e) a semiconductor layer of a second conduction type that is formed on the light absorption layer; and f) a high-concentration semiconductor intermediate tunneling layer of the first conduction type that is interposed between the buffer layer and the light absorption layer and has a higher impurity concentration than the buffer layer, the semiconductor intermediate tunneling layer allowing electrons to pass therethrough to the buffer layer due to a tunnel effect, wherein said semi-insulating substrate and layers b)-f) are arranged to form a semiconductor light-receiving device, the high-concentration semiconductor intermediate tunneling layer and the buffer layer being made of an identical material, and wherein the light absorption layer directly contacts the high-concentration semiconductor intermediate tunneling layer.