Avalanche photodiode

US7557387B2 · kind B2 · utility

Assignees

• NIPPON TELEGRAPH AND TELEPHONE CORPORATION · JP
• NTT Electronics Corporation · JP

Inventors

• Tadao Ishibashi · Yokohama, JP
• Seigo Ando · Tokyo, JP
• Yukihiro Hirota · Atsugi, JP

Key dates

• Filing date: Feb 3, 2005
• Grant date: Jul 7, 2009
• Expiry date: Jan 9, 2026

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10F30/2255

Abstract

An ultra high speed APD capable of realizing reduction in an operating voltage and quantum efficiency enhancement at the same time is provided. Under operating conditions APD, a doping concentration distribution of each light absorbing layer is determined so that a p-type light absorbing layer (16) maintains a p-type neutrality except a part thereof, and a low concentration light absorbing layer (15) is depleted. Moreover, a ratio between a layer thickness WAD of the p-type light absorbing layer (16) and a layer thickness WAD of the low concentration light absorbing layer (15) is determined so that WAD>0.3 μm and a delay time of an element response accompanying a transit of carriers generated in the light absorbing layer by light absorption takes on a local minimum under a condition that a layer thickness WA (=WAN+WAD) of the light absorbing layer is constant.