Photodetection element

Patent metadata

Field	Value
Publication number	US-10686094-B2
Application number	US-201816114360-A
Country	US
Kind code	B2
Filing date	Aug 28, 2018
Priority date	Sep 5, 2017
Publication date	Jun 16, 2020
Grant date	Jun 16, 2020

Abstract

A photodetection element includes a semiconductor layer having, on one surface side, a periodic concave/convex structure that includes periodic convex portions and concave portions and converts light into surface plasmon, and a metal film provided on the one surface side of the semiconductor layer in correspondence to the periodic concave/convex structure, and in the periodic concave/convex structure, a Schottky junction portion that has a Schottky junction with the metal film is provided on a base end side of the convex portion, and a non-Schottky junction portion that does not have a Schottky junction with the metal film is provided on a distal end side of the convex portion.

First claim

What is claimed is:

1. A photodetection element, comprising:
a semiconductor layer having, on one surface side, a periodic concave/convex structure that includes periodic convex portions and concave portions and, on an other surface side, an incidence surface for light, wherein the periodic concave/convex structure converts light incident from the incident surface into surface plasmon; and
a metal film provided on the one surface side of the semiconductor layer in correspondence to the periodic concave/convex structure,
wherein in the periodic concave/convex structure, a Schottky junction portion that has a Schottky junction with the metal film is provided on a base end side of the convex portion, and a non-Schottky junction portion that does not have a Schottky junction with the metal film is provided on a distal end side of the convex portion,
wherein an insulating film is provided on a top surface of the convex portions,
the metal film includes a first portion covering a bottom surface and an inner wall surface of the concave portion, and a second portion covering the insulating film, and
the Schottky junction portion is formed of the first portion, and the non-Schottky junction portion is formed of the second portion.

2. The photodetection element according to claim 1 , wherein a refractive index of the insulating film is smaller than a refractive index of the semiconductor layer.

3. The photodetection element according to claim 1 , wherein a thickness of the metal film is equal to or greater than 20 nm.

4. The photodetection element according to claim 1 , wherein the semiconductor layer is formed of silicon.

5. The photodetection element according to claim 1 , wherein the metal film includes aluminum.

6. The photodetection according to claim 1 , wherein the metal film is formed of a plurality of films including a first film in contact with the semiconductor layer and a second film with a refractive index smaller than that of the first film element.

Assignees

• Hamamatsu Photonics Kk

Inventors

• Dong Wei
• Fujiwara Hiroyasu
• Nakajima Kazutoshi

Classifications

• H10F77/413

  directly associated or integrated with the devices, e.g. back reflectors (directly associated or integrated with photovoltaic cells H10F77/42) · CPC title

• H10F77/148

  Shapes of potential barriers · CPC title

• H10F77/147

  Shapes of bodies · CPC title

• H10F77/70

  Surface textures, e.g. pyramid structures · CPC title

• H10F77/20

  Electrodes · CPC title