LIGHT RECEIVING ELEMENT AND METHOD FOR MANUFACTURING SAME

• US 20140319464A1
• Filed: 06/11/2012
• Published: 10/30/2014
• Est. Priority Date: 12/14/2011
• Status: Abandoned Application

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Iguchi, Yasuhiro
• Application Number:
  US14/365,515
• Publication Number:
  US 20140319464A1
• Time in Patent Office: Days
• US Class Current: 257/21
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 27/14647 Multicolour imagers having a stacked pixel-element structure, e.g. npn, npnpn or MQW elements
• CPC Class Codes: H01L 31/02161 for devices characterised by at least one potential jump barrier or surface barrier
• CPC Class Codes: H01L 31/022408 for devices characterised by at least one potential jump barrier or surface barrier
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: H01L 31/035236 Superlattices; Multiple quantum well structures
• CPC Class Codes: H01L 31/105 the potential barrier being of the PIN type
• CPC Class Codes: H01L 31/109 the potential barrier being of the PN heterojunction type
• CPC Class Codes: H01L 31/18 Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A light-receiving element includes a light-receiving layer for receiving light, the light-receiving layer being disposed on a semiconductor substrate, a contact layer disposed on the light-receiving layer, and a pixel electrode that is in ohmic contact with the contact layer. A back surface of the semiconductor substrate functions as a light-incident surface, and a reaction-preventing film for preventing a chemical reaction between the contact layer and the pixel electrode is interposed in a predetermined region between the contact layer and the pixel electrode.

Claims

1. A light-receiving element including a pixel comprising:

a semiconductor substrate having a back surface including a light-incident surface;

a light-receiving layer for receiving light, the light-receiving layer being disposed on the semiconductor substrate;

a contact layer disposed on the light-receiving layer;

a reaction-preventing film disposed on the contact layer, the reaction-preventing film having an opening; and

a pixel electrode disposed on the reaction-preventing film,

wherein the pixel electrode is formed in the opening, and

the pixel electrode is in ohmic contact with the contact layer through the opening.

2. The light-receiving element according to claim 1, wherein the pixel electrode is in contact with the reaction-preventing film at a region including a center of the pixel electrode, and

the opening of the reaction-preventing film is located at a peripheral portion of the reaction-preventing film.

3. The light-receiving element according to claim 1, further comprising a protective film that covers at least a surface of the contact layer around the pixel electrode,

wherein the opening is disposed between the reaction-preventing film and the protective film on the contact layer, and

the reaction-preventing film has a thickness smaller than a thickness of the protective film.

4. The light-receiving element according to claim 1, wherein the reaction-preventing film is at least one of a silicon nitride (SiN) film, a silicon oxynitride (SiON) film, and a silicon oxide (SiO₂) film.

5. The light-receiving element according to claim 1, wherein the light-receiving layer includes a p-n junction, therein.

6. The light-receiving element according to claim 1, wherein the light-receiving layer has a type-II multi-quantum well (MQW) structure.

7. A method for manufacturing a light-receiving element including a pixel, the method comprising the steps of:

forming a light-receiving layer on a semiconductor substrate;

forming a contact layer on the light-receiving layer;

forming a reaction-preventing film on the contact layer, the reaction-preventing film has a first opening at a peripheral portion of the reaction-preventing film, the contact layer being exposed through the first opening;

forming a pixel electrode on the reaction-preventing film and in the first opening of the reaction-preventing film, the pixel electrode being in contact with the contact layer through the first opening; and

conducting heat treatment to the pixel electrode so that the pixel electrode in the first opening and the contact layer chemically react each other to establish ohmic contact.

8. The method for manufacturing a light-receiving element according to claim 7, after the step of forming the contact layer, further includes a step of forming a protective film on the contact layer other than a region on which the pixel electrode is to be provided,

wherein the step of forming the reaction-preventing film includes the steps of:

forming an insulating layer on the protective film and on the contact layer;

forming a mask on the insulating layer, the mask having a pattern including the first opening of the reaction-preventing film; and

etching the insulating layer so as to form the reaction-preventing film using the mask.

9. The method for manufacturing a light-receiving element according to claim 7, further includes steps of:

forming on the contact layer between the step of forming the contact layer and the step of forming the reaction-preventing film, the selective diffusion mask having a pattern including a second opening; and

selectively diffusing an impurity through the second opening using the selective diffusion mask at a predetermined temperature,

wherein the step of forming the reaction-preventing film includes the steps of;

forming an insulating layer on the selective diffusion mask and on the contact layer exposed through the second opening after selectively diffusing the impurity;

forming a mask on the insulating layer, the mask having a pattern including the first opening of the reaction-preventing film; and

etching the insulating layer so as to form the reaction-preventing film using the mask.

10. The method for manufacturing a light-receiving element according to claim 9, wherein the selective diffusion mask is left on the contact layer without removing after selectively diffusing the impurity, and

the selective diffusion mask functions as a protective film.

11. The method for manufacturing a light-receiving element according to claim 7, further includes the steps of:

forming a mesa structure defined by a groove on the semiconductor substrate between the step of forming the contact layer and the step of the reaction-preventing film, the mesa structure including the light-receiving layer and the contact layer formed on the light-receiving layer,

forming a protective layer on the contact layer and on a side surface of the mesa structure, the protective layer has a third opening,

wherein the step of forming the reaction-preventing film includes the steps of;

forming an insulating layer on an entire surface is of the semiconductor substrate;

forming a mask on the insulating layer, the mask having a pattern including the first opening of the reaction-preventing film; and

etching the insulating layer so as to form the reaction-preventing film in the third opening of the protective layer using the mask.