Semiconductor device and method for producing the same

• US 20020025597A1
• Filed: 10/18/2001
• Published: 02/28/2002
• Est. Priority Date: 11/19/1998
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Matsuda, Kenichi
• Granted Patent: US 6,458,620 B1
• Time in Patent Office: Days
• US Class Current: 438/57
• CPC Class Codes: H01L 31/02164 for shielding light, e.g. light blocking layers, cold shields for infrared detectors
• CPC Class Codes: H01L 31/022416 comprising ring electrodes
• CPC Class Codes: H01L 31/103 the potential barrier being of the PN homojunction type
• CPC Class Codes: H01L 31/105 the potential barrier being of the PIN type
• CPC Class Codes: H01L 31/1804 comprising only elements of Group IV of the Periodic Table
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A photo-detecting device includes: a semiconductor substrate; a multilayer structure formed on the semiconductor substrate; an island-like photo-detecting region formed in at least a portion of the multilayer structure, the island-like photo-detecting region having a central portion; and a light -shielding mask formed on the semiconductor substrate so as to shield from light a portion of the island-like photo-detecting region at least excluding the central portion. The light-shielding mask comprises an upper metal film and a lower metal film, and the upper metal film and the lower metal film are at least partially isolated by an insulative film, the upper metal film and the lower metal film having different patterns.

Claims

1. A photo-detecting device comprising:

a semiconductor substrate;

a multilayer structure formed on the semiconductor substrate;

an island-like photo-detecting region formed in at least a portion of the multilayer structure, the island-like photo-detecting region having a central portion; and

a light-shielding mask formed on the semiconductor substrate so as to shield from light a portion of the island-like photo-detecting region at least excluding the central portion,

wherein the light-shielding mask comprises an upper metal film and a lower metal film, and

the upper metal film and the lower metal film are at least partially isolated by an insulative film, the upper metal film and the lower metal film having different patterns.

2. A photo-detecting device according to claim 1,

wherein the upper metal film and the lower metal film each have an inner end portion located adjacent to the photo-detecting region,

wherein the inner end portion of the upper metal film is located more closely to the photo-detecting region, along a horizontal direction, than the inner end portion of the lower metal film, and

the upper metal film is not provided in a further region which is located at a predetermined distance from the photo-detecting region, the further region being shielded from light by the lower metal film.

3. A photo-detecting device according to claim 1, wherein wherein the inner end portion of the upper metal film is in an overlapping relation with the photo-detecting region.

4. A photo-detecting device according to claim 1, wherein the upper metal film is electrically coupled with the lower metal film via an opening in the insulative film.

5. A photo-detecting device according to claim 1,

wherein an outer end portion of the semiconductor substrate is shielded from light by the lower metal film, and

wherein the insulative film and the upper metal film are not formed at in the outer end portion of the semiconductor substrate.

6. A photo-detecting device comprising:

a semiconductor substrate;

a light absorption layer and a window layer formed in this order on the semiconductor substrate;

a diffusion region formed in an island-like shape in the window layer;

a negative electrode formed on a portion of the diffusion region;

an insulative film formed on a portion of the window layer at least excluding a central portion of the diffusion region;

a pad formed on a region of the insulative film which is located at a predetermined distance from the diffusion region;

wiring formed on the insulative film for electrically connecting the negative electrode with the pad;

an upper metal film formed on the insulative film so as to surround the diffusion region without overlapping the wiring; and

a lower metal film formed between the window layer and the insulative film,

wherein the negative electrode, the pad, the wiring, and the upper metal film are formed from the same thin metal film.

7. A photo-detecting device according to claim 6, wherein substantially the entire diffusion region above the semiconductor substrate at least excluding the central portion is shielded from light by at least one of the upper metal film and the lower metal film.

8. A photo-detecting device according to claim 7, further comprising a positioning mark formed in a portion of the diffusion region above the semiconductor substrate at least excluding the central portion, the positioning mark being shielded from light by neither the upper metal film nor the lower metal film.

9. A photo-detecting device according to claim 6, further comprising a contact hole and a positive electrode,

wherein the contact hole is located in a region where the window layer and the light absorption layer above the semiconductor substrate has been removed, and

wherein the positive electrode comprises a portion of the lower metal film which is present in an exposed surface of the contact hole.

10. A photo-detecting device according to claim 6, further comprising a positive electrode formed on the semiconductor substrate and a back face metal film formed on a back face of the semiconductor substrate.

11. A photo-detecting device according to claim 6, further comprising a side face metal film formed on at least one side face of the semiconductor substrate, the light absorption layer, and the window layer.

13. A method for producing a photo-detecting device according to claim 12, wherein the lower metal film is a lamination film comprising Cr, Pt, and Au.

12. A method for producing a photo-detecting device comprising the steps of:

growing a light absorption layer and a window layer on a semiconductor substrate in this order;

forming an island-like diffusion region in the window layer by diffusing an impurity therein;

depositing a lower metal film on a portion of the window layer excluding the island-like diffusion region;

depositing an insulative film on the window layer and the lower metal film;

forming an opening over the island-like diffusion region by partially etching away the insulative film;

depositing and lifting off a thin metal film so as to simultaneously form a negative electrode, a pad, wiring, and an upper metal film.