Semiconductor detector for infrared radiation and method for manufacturing same

• US 5,939,722 A
• Filed: 10/28/1997
• Issued: 08/17/1999
• Est. Priority Date: 10/31/1996
• Status: Expired due to Term

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Werner, Wolfgang, Bruchhaus, Rainer, Wersing, Wolfram
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): HANIG, RICHARD E
• Application Number:
  US08/958,582
• Time in Patent Office: 658 Days
• Field of Search: 250/338.4, 250/338.1, 250/370.01, 257/684, 438/73, 216/2
• US Class Current: 250/338.4
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/024 Special manufacturing steps or sacrificial layers or layer structures
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/045 Sealings; Vacuum enclosures; Encapsulated packages; Wafer bonding structures; Getter arrangements getter arrangements per se H01L23/26 and H01L21/3221
• CPC Class Codes: G01J 5/10 using electric radiation detectors
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: G01J 5/34 using capacitors, e.g. pyroelectric capacitors
• CPC Class Codes: H10N 15/10 Thermoelectric devices using thermal change of the dielectric constant, e.g. working above and below the Curie point

Abstract

A semiconductor detector for infrared radiation is manufactured by the steps of depositing an auxiliary layer on a main surface of a carrier, depositing a membrane layer provided with at least one opening onto the auxiliary layer, selectively etching the auxiliary layer through the at least one opening of the membrane layer, so that a hollow space arises in the auxiliary layer, sealing the hollow space by depositing a covering on th membrane layer, and fashioning a detector element on the covering by depositing a material sensitive to infrared radiation within a region of the covering that is bounded by the hollow space therebelow.

Claims

1. A method for manufacturing a semiconductor detector for infrared radiation, comprising the steps of:

depositing an auxiliary layer on a primary surface of a carrier;

depositing a membrane layer, with at least one opening therein, onto said auxiliary layer;

selectively etching said auxiliary layer through said at least one opening in said membrane layer for producing a hollow space in said auxiliary layer;

sealing said hollow space by depositing a covering over said membrane layer; and

depositing infrared radiation-sensitive material on said covering within a region of said covering limited by the hollow space therebelow.

2. A method as claimed in claim 1 comprising the additional step of evacuating said hollow space while depositing said covering.

3. A method as claimed in claim 1 wherein the step of selectively etching said auxiliary layer comprises selectively etching said auxiliary layer with isotropic components and leaving a portion of the material of said auxiliary layer standing inside hollow space for forming a support for said membrane layer and said covering.

4. A method as claimed in claim 1 comprising the additional steps of:

providing a semiconductor substrate as said carrier;

forming a semiconductor circuit on said primary surface of said semiconductor substrate outside of said region limited by said hollow space; and

electrically coupling said semiconductor circuit to said infrared radiation-sensitive material.

5. A method as claimed in claim 1 comprising the additional steps of:

depositing a lower electrode on said covering before depositing said infrared radiation-sensitive material; and

depositing and structuring an upper electrode on said infrared radiation-sensitive material after depositing said infrared radiation-sensitive material.

6. A method as claimed in claim 5 comprising the additional step of:

laterally attaching an insulator to said infrared radiation-sensitive material for electrically insulating said lower electrode from said upper electrode.

7. A method as claimed in claim 1 comprising the additional step of employing a ferroelectric dielectric as said infrared radiation-sensitive material.

8. A method as claimed in claim 7 comprising the additional step of selecting said ferroelectric dielectric from the group consisting of lead, zirconate, titanate and lead titanate.

9. A method as claimed in claim 1 wherein the step of depositing said covering comprises depositing a thermally insulating material as said covering.

10. A method as claimed in claim 9 comprising the additional step of selecting said thermally insulating material from at least one material in the group consisting of polysilicon, nitrides, and glasses.

11. A method as claimed in claim 9 comprising the additional step of selecting said thermally insulating material from at least one material in the group consisting of polysilicon, nitrides, and phosphor glass.

12. A method as claimed in claim 1 wherein said auxiliary layer comprises a first auxiliary layer and wherein said membrane layer comprises a first membrane layer and wherein said at least one hollow space comprises at least one first hollow space, said method comprising the additional steps of:

depositing a further auxiliary layer over said first membrane layer;

depositing a further membrane layer over said further auxiliary layer, said further membrane layer having at least one opening therein;

selectively etching said further auxiliary layer through said at least one opening in said further membrane layer simultaneously with etching said first auxiliary layer, for producing at least one further hollow space in said further auxiliary layer simultaneously with said first hollow space in said auxiliary layer; and

depositing said covering over said further membrane layer for sealing said first and second hollow spaces.

13. A semiconductor detector for infrared radiation, comprising:

a carrier and auxiliary layer deposited on a primary surface of said carrier;

a membrane layer, with at least one opening therein, deposited onto said auxiliary layer;

said auxiliary layer having at least one hollow space therein selectively etched through said at least one opening in said membrane layer;

a covering deposited over said membrane layer and sealing said hollow space; and

infrared radiation-sensitive material deposited on said covering within a region of said covering limited by the hollow space therebelow.

14. A detector as claimed in claim 13 wherein said auxiliary layer comprises a portion of the material of said auxiliary layer left standing inside hollow space after selectively etching said auxiliary layer forming a support for said membrane layer and said covering.

15. A detector as claimed in claim 13 wherein said carrier is a semiconductor substrate, and said detector further comprising:

a semiconductor circuit on said primary surface of said semiconductor substrate outside of said region limited by said hollow space; and

connections electrically coupling said semiconductor circuit to said infrared radiation-sensitive material.

16. A detector as claimed in claim 13 further comprising:

a lower electrode deposited on said covering before depositing said infrared radiation-sensitive material; and

depositing and structuring an upper electrode on said infrared radiation-sensitive material after depositing said infrared radiation-sensitive material.

17. A detector as claimed in claim 16 comprising:

an insulator laterally attached to said infrared radiation-sensitive material for electrically insulating said lower electrode from said upper electrode.

18. A detector as claimed in claim 13 wherein said infrared radiation-sensitive material comprises a ferroelectric dielectric.

19. A detector as claimed in claim 18 wherein said ferroelectric dielectric is selected from the group consisting of lead, zirconate, titanate and lead titanate.

20. A detector as claimed in claim 13 wherein said covering comprises a thermally insulating material.

21. A detector as claimed in claim 20 wherein said thermally insulating material is selected from at least one material in the group consisting of polysilicon, nitrides, and glasses.

22. A detector as claimed in claim 20 wherein said thermally insulating material is selected from at least one material in the group consisting of polysilicon, nitrides, and phosphor glass.

23. A detector as claimed in claim 13 wherein said auxiliary layer comprises a first auxiliary layer and wherein said membrane layer comprises a first membrane layer and wherein said at least one hollow space comprises at least one first hollow space, said detector further comprising:

a further auxiliary layer deposited over said first membrane layer;

a further membrane layer deposited over said further auxiliary layer, said further membrane layer having at least one opening therein;

said further auxiliary layer having at least one further hollow space therein selectively etched through said at least one opening in said further membrane layer simultaneously with etching said first auxiliary layer; and

said covering being deposited over said further membrane layer and sealing both said first and second hollow spaces.