Semiconductor photo-detector

Abstract

Abstract PURPOSE: To provide a planer construction APD (avalanche photo diode) small in the dark current and the junction capacity reducing the process by forming the pn- conjunction under the photo detecting surface in or in contact with a semiconductor material having a band gap smaller than the pn-junction around the surface. CONSTITUTION: An epitaxial layer 10 of n-type InGaAsP or InP is made to frow on an n + -type InP substrate 9 and a mesa etching is conducted to remove all thereof but the central portion. Then, an n-type InP layer 11 is made to grow on the entire substrate including the central portion and a p-type region 3 is formed on the layer 11 by diffusion reaching the layer 10. Otherwise, the continuous epitaxial growth of the layer 11 may be done on the layer 10 and then, a partial etching is conducted to form a region 3 in an area including the layer 10. It also may be accepted that the layers 10 and 11 are further continuously grown with the front of the region 3 demarcated near the interface between the layers 10 and 11. This allows the breakdown voltage to be almost equal to that of the pn-junction with a curvature around the photo detecting surface reducing the diffusion process, making the device ideal for APD very small in the photo detecting diameter. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Yoshihisa Yamamoto
• 👤 Hiroshi Kanbe

Bibliographic Details