Semiconductor-based radiation-detector element

• US 5,156,979 A
• Filed: 05/07/1991
• Issued: 10/20/1992
• Est. Priority Date: 01/21/1986
• Status: Expired due to Fees

• Current Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Inventors: Suzuki, Toshikazu, Sato, Noritada, Ishiwata, Osamu
• Primary Examiner(s): Chaudhuri, Olik
• Assistant Examiner(s): TRINH, LOC
• Application Number:
  US07/664,825
• Time in Patent Office: 532 Days
• Field of Search: 437/3, 437/20, 437/23, 437/24, 437/929, 357/9, 357/15, 357/17, 357/29, 148/DIG. 95, 148/DIG. 128, 372/44, 372/46, 376/147
• US Class Current: 438/56
• CPC Class Codes: G01T 3/08 with semiconductor detectors
• CPC Class Codes: H01L 31/115 Devices sensitive to very short wavelength, e.g. X-rays, gamma-rays or corpuscular radiation
• 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: Y10S 438/918 Special or nonstandard dopant

Abstract

A semiconductor-based radiation-detector element particularly adapted to neutron detection, and the method for making the same, in which a high sensitivity single-crystal semiconductor substrate has diffused therein at-least-one region of ³ He gas, which remain resident therein, whereby, upon application of an inverse bias to the junction in the semiconductor substrate, the colliding of incident neutrons with the resident ³ He gas results in a reaction which produces hole-electron pairs in the depletion layer within the semiconductor, those hole-electron pairs producing output electrical pulses which appear at the output terminals of the detector for utilization by detection and measuring apparatus connected to the semiconductor-based radiation-detector element.

Claims

1. The method of fabricating a detecting element for a semiconductor-based radiation detector including the steps of:

providing a substrate of single-crystal silicon having first and second opposite surfaces;

diffusing a region of ³ He into at least one of the first and second opposite surfaces of said substrate, said ³ He region being formed by a low-temperature plasma CVD doping process;

depositing a metal on the first surface of said substrate, said metal making a rectifying connection to the first surface of said substrate; and

depositing a metal on the second surface of said substrate, said metal making an ohmic connection to the second surface of said substrate.

2. The method according to claim 1 in which the temperature of said low temperature plasma CVD doping process is not greater than 200°

C.

3. The method according to claim 1 in which a region of ³ He is diffused into only one of the first and second surfaces of said substrate, said method including the additional step of forming a p⁺ region in the surface opposite the surface proximate to that in which said ³ He region is formed, said p⁺ region being formed by diffusing boron into said substrate through said opposite surface.

4. The method of fabricating a detecting element for a radiation-based radiation detector which includes the steps of:

diffusing ³ He into one surface of a single-crystal silicon substrate having opposing surfaces;

laminating amorphous silicon onto at least one of the opposite surfaces of said single-crystal silicon substrate to form a heterojunction with said single-crystal substrate using a low-temperature plasma method; and

depositing by a vapor deposition step a first ohmic contact on said amorphous silicon and a second ohmic contact on the surface of said single-crystal substrate opposite that on which said amorphous silicon is laminated.

5. The method of fabricating a detecting element for a radiation-based radiation detector which includes the steps of:

providing a substrate of single-crystal silicon having first and second opposite surfaces;

diffusing a region of ³ He into at least one of the first and second opposite surfaces of said substrate, said ³ He region being formed by a low-temperature plasma CVD doping process;

laminating amorphous silicon onto at least one of the opposite surfaces of said single-crystal silicon substrate to form a heterojunction with said single-crystal substrate using a low-temperature plasma CVD method; and

depositing by a vapor deposition step a first ohmic contact on said amorphous silicon and a second ohmic contact on the surface of said single-crystal substrate opposite that on which said amorphous silicon is laminated.

6. The method according to claim 5 wherein said amorphous silicon is laminated onto the surface into which said ³ He is diffused.

7. The method according to claim 6 wherein a p⁺ region is interposed between said substrate and the second ohmic contact.