Optical detector

Patent metadata

Field	Value
Publication number	US-12000779-B2
Application number	US-202117543936-A
Country	US
Kind code	B2
Filing date	Dec 7, 2021
Priority date	Dec 25, 2020
Publication date	Jun 4, 2024
Grant date	Jun 4, 2024

Abstract

An optical detector includes a semiconductor base portion of a first conductivity type having a first surface and a second surface and provided with a projection projecting from the second surface, a first metal electrode layer provided on the first surface or the second surface of the semiconductor base portion, a semiconductor layer of a second conductivity type having a first portion covering the second surface of the semiconductor base portion and second portions covering side surfaces of the projection, and a second metal electrode layer provided in close contact with the second semiconductor layer such that the projection and the second portions of the second semiconductor layer are interposed therebetween. An MIM resonator is constituted by the projection, the second portions of the second semiconductor layer, and the second metal electrode layer between which the projection and the second portions of the semiconductor layer are interposed.

First claim

What is claimed is:

1. An optical detector comprising:
a semiconductor base portion constituted by a first conductivity type semiconductor, having a first surface and a second surface facing the first surface, and provided with a projection projecting from the second surface;
a first metal electrode layer provided on the first surface or the second surface of the semiconductor base portion;
a semiconductor layer constituted by a second conductivity type semiconductor and having a first portion covering the second surface of the semiconductor base portion and second portions covering side surfaces of the projection; and
second metal electrode layers provided in close contact with the semiconductor layer such that the projection and the second portions of the semiconductor layer are interposed therebetween,
wherein an MIM resonator is constituted by the projection, the second portions of the semiconductor layer, and the second metal electrode layers between which the projection and the second portions of the semiconductor layer are interposed, and
wherein a resonator length of the MIM resonator is a length in which a surface plasmon is excited by incident light having a wavelength longer than the wavelength of absorption edge of each of the semiconductor base portion and the semiconductor layer and a phonon is excited by an electric field formed by a resonance of the surface plasmon.

2. The optical detector according to claim 1 , wherein, in the semiconductor layer, a thickness of each of the second portions is smaller than a thickness of the first portion.

3. The optical detector according to claim 1 ,
wherein the semiconductor layer has a third portion covering a top surface of the projection, and
wherein the second metal electrode layers have an electrode portion therebetween covering the third portion of the semiconductor layer and connecting portions between which the projection and the second portions of the semiconductor layer are interposed.

4. The optical detector according to claim 1 ,
wherein an insulating layer is provided on a top surface of the projection across the top surface and the second portions of the semiconductor layer, and
wherein the second metal electrode layers have an electrode portion therebetween covering the insulating layer.

5. The optical detector according to claim 1 , wherein, in a case in which a wavelength of the surface plasmon is λp, a height H of the projection from the first portion of the semiconductor layer satisfies 2/8 λp<H<5/8 λp.

6. The optical detector according to claim 1 ,
wherein a plurality of the projections are provided at regular intervals in an in-plane direction of the second surface of the semiconductor base portion, and
wherein, in a case in which a wavelength of the surface plasmon is λp, a pitch P from a side surface of one projection to the same side surface of an adjacent projection satisfies 9/10 λp<P<11/10 λp.

Assignees

• Hamamatsu Photonics Kk

Inventors

• Dong Wei

Classifications

• H10F77/147

  Shapes of bodies · CPC title

• H10F77/413

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

• H10F77/206

  for devices having potential barriers · CPC title

• H10F30/10 Primary

  the devices being sensitive to infrared radiation, visible or ultraviolet radiation, and having no potential barriers, e.g. photoresistors · CPC title

• G01N21/45 Primary

  using interferometric methods; using Schlieren methods · CPC title