Semiconductor photodetector with improved quantum efficiency as a function of detected light wavelength

US8035181B2 · kind B2 · utility

Assignee

• Mitsubishi Electric Corporation · JP

Inventors

• Eitaro Ishimura · Tokyo, JP
• Masaharu Nakaji · Tokyo, JP

Key dates

• Filing date: Dec 4, 2008
• Grant date: Oct 11, 2011
• Expiry date: Dec 4, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02E10/544

Abstract

A semiconductor photodetector comprises: a semiconductor substrate; a first multilayer reflective layer on a first surface of the semiconductor substrate and including semiconductor layers; a first optically-resonant layer on the first multilayer reflective layer; a second multilayer reflective layer on the first optically-resonant layer and including semiconductor layers; a light absorbing layer on the second multilayer reflective layer; a reflective film on the light absorbing layer; and an antireflective film on a second surface of the semiconductor substrate. The first optically-resonant layer has a larger thickness than the semiconductor layers of the first and second multilayer reflective layers. The combined optical thickness of the layers between the second multilayer reflective layer and the reflective film is not equal to the optical thickness of the first optically-resonant layer.