Method of fabrication of an infrared radiation detector and infrared detector device

• US 6,884,636 B2
• Filed: 05/18/2001
• Issued: 04/26/2005
• Est. Priority Date: 03/28/1997
• Status: Expired due to Term

• Current Assignee: Interuniversitair Micro-Electronica Centrum VZW (IMEC International)
• Original Assignee: Interuniversitair Micro-Electronica Centrum VZW (IMEC International)
• Inventors: Fiorini, Paolo, Sedky, Sherif, Caymax, Matty, Baert, Christiaan
• Primary Examiner(s): Fourson, George
• Assistant Examiner(s): Toledo, Fernando
• Application Number:
  US09/861,334
• Publication Number:
  US 20010055833A1
• Time in Patent Office: 1,439 Days
• Field of Search: 438/14, 438/478, 438/149, 250/338.1
• US Class Current: 438/14
• CPC Class Codes: B81C 1/00666 Treatments for controlling internal stress or strain in MEMS structures
• CPC Class Codes: B81C 2201/017 Methods for controlling internal stress of deposited layers not provided for in B81C2201/0164 - B81C2201/0169
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: H01L 31/09 Devices sensitive to infrared, visible or ultraviolet radiation H01L31/101 takes precedence
• 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 method of fabricating an infrared detector, a method of controlling the stress in a polycrystalline SiGE layer and an infrared detector device is disclosed. The method of fabricating includes the steps of forming a sacrificial layer on a substrate; patterning said sacrificial layer; establishing a layer consisting essentially of polycrystalline SiGe on said sacrificial layer; depositing an infrared absorber on said polycrystalline SiGe layer; and thereafter removing the sacrificial layer. The method of controlling the stress in a polycrystalline SiGe layer deposited on a substrate is based on varying the deposition pressure. The infrared detector device comprises an active area and an infrared absorber, wherein the active area comprises a polycrystalline SiGe layer, and is suspended above a substrate.

Claims

1. A method of fabricating an electrical device comprising:

depositing a sacrificial layer comprising a first material on a substrate;

depositing a second material on the substrate;

contemporaneously forming an active layer portion and at least one connector portion from the second material, wherein the connector electrically couples the active layer portion with circuitry included on the substrate; and

removing at least a portion of the sacrificial layer.

2. The method of claim 1, wherein depositing a sacrificial layer includes forming a sacrificial layer on the substrate and patterning the sacrificial layer.

3. The method of claim 1, wherein the second material consists essentially of a single material.

4. The method of claim 3, wherein the single material comprises polycrystalline silicon.

5. The method of claim 3, wherein the single material comprises silicon-germanium.

6. The method of claim 3, wherein forming the active layer portion and the at least one connector portion comprises:

patterning the second material, so as to contemporaneously form the active area portion, the at least one connector portion and at least one support of the active layer.

7. The method of claim 6, wherein forming the active layer portion and the at least one connector portion further comprises:

doping the active layer portion and the at least one connector portion after pattering the second material.

8. A method of fabricating an electrical device comprising:

depositing a sacrificial layer on a substrate;

forming an active area;

forming at least one connector, the connector electrically contacting the active area with circuitry included on the substrate; and

removing at least a portion of the sacrificial layer,

wherein the active area and the connector consist essentially of a single material, and the active area is suspended above the substrate using one or more supports Conned with the active area.

9. The method of claim 8, wherein forming the active area and forming the at least one connector is performed substantially simultaneously.

10. The method of claim 9, wherein forming the active area and forming the at least one connector comprises:

patterning the active area and the at least one connector.

11. The method of claim 10, wherein forming the active area and forming the at least one connector further comprises:

doping the active area and the at least one connector.

12. The method of claim 9, further comprising:

doping the electrical device after forming.

13. The method of claim 12, wherein doping includes performing doping of the at least one connector with a different doping concentration than the active area.

14. The method of claim 13, wherein doping the at least one connector includes highly doping the at least one connector.

15. The method of claim 12, wherein doping includes performing doping of the active area and the at least one connector.

16. The method of claim 11, wherein doping of the active area and the at least one connector includes moderately doping the active area and the at least one connector.

17. The method of claim 8, wherein the electrical device comprises an infrared device.

18. The method of claim 8, wherein the electrical device comprises a detector.

19. The method of claim 8, wherein the single material comprises polycrystalline.

20. The method of claim 8, wherein the single material comprises silicon-germanium.

21. The method of claim 8, wherein removing includes removing substantially all of the sacrificial layer.

22. The method of claim 8, wherein depositing the sacrificial layer comprises:

forming a sacrificial layer on the substrate; and

patterning the sacrificial layer.

23. The method of claim 8, wherein the active area comprises a material made of polycrystalline Si_70%Ge_30%.

24. The method of claim 23, wherein the active area is deposited by chemical vapor deposition.

25. The method of claim 23, wherein the active area is deposited at or below atmospheric pressure.