Hitachi, Ltd.

Ichiro Fujiwara

Hiroshi Matsuda

Kazuhiro Ito

Kazuyuki Nagatsuma

Hirobumi Ouchi

A semiconductor photodetector is disclosed which comprises a pn junction formed in a semiconductor substrate and a pair of electrodes for applying a reverse bias to the pn junction, in which at least a part of the junction plane of the pn junction has been metamorphosed by enhanced diffusion. Hence the pn junction from an outer peripheral portion and a central portion is made smooth.

Fabricating a semiconductor photodetector by annealing to smooth the PN

An avalanche photodiode including a substrate, a first semiconductor region of a first conductivity type having a relatively large band gap, a second semiconductor region of a second conductivity type having a relatively large band gap, and a third semiconductor region of the first conductivity type having a band gap smaller than the band gap of the first and second semiconductor regions, is disclosed in which, in order to suppress an increase in dark current and to cause the avalanche photodiode to operate on a low voltage, a fourth semiconductor region equal in conductivity type to and larger in impurity concentration than the first semiconductor region is formed in the first semiconductor region at a position below a central portion of a pn junction formed between the first semiconductor region and the second semiconductor region. The avalanche photodiode formed with this structure has low-noise and low operation voltage characteristics.

Growing community of inventors

Kawasaki, Japan

Ichiro Fujiwara