US4060432A
Expired / Lapsed
US
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Method for manufacturing nuclear radiation detector with deep diffused junction
Assignee: General Electric Co
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Filing: 1975-10-20
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Granted: 1977-11-29
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Expires: 1995-10-20
Abstract
Abstract Germanium radiation detectors are manufactured by diffusing lithium into high purity p-type germanium. The diffusion is most readily accomplished from a lithium-lead-bismuth alloy at approximately 430° C. and is monitored by a quartz half cell containing a standard composition of this alloy. Detectors having n-type cores may be constructed by converting high purity p-type germanium to n-type by a lithium diffusion and subsequently diffusing some of the lithium back out through the surface to create a deep p-n junction. Coaxial germanium detectors comprising deep p-n junctions are produced by the lithium diffusion process.
Inventors
- 👤 Robert N. Hall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:10
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/24; H; H10; H10F; H10F30/00; H10F30/20; H10F30/29; H10F30/292; H10F30/2925; H10P; H10P32/00; H10P32/10; H10P32/16
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
62 words
A method for manufacturing deep junctions in germanium bodies comprising: forming a body of high purity p-type germanium having an initial acceptor concentration and diffusing lithium, from a precalculated concentration of lithium, deep into said body, in the absence of electrolytic processes within said body, to form a junction of high purity n-type germanium and high purity p-type germanium within said body.
Claim 2
Independent Claim
62 words
A method for manufacturing deep junctions in germanium bodies comprising: forming a body of high purity p-type germanium having an initial acceptor concentration and diffusing lithium, from a precalculated concentration of lithium, deep into said body, in the absence of electrolytic processes within said body, to form a junction of high purity n-type germanium and high purity p-type germanium within said body.
Claim 3
Dependent Claim
32 words
The method of claim 1 wherein said precalculated lithium concentration at the surface of said body is between approximately 1.5 and approximately 4 times the initial acceptor atom concentration in said body.
Claim 4
Dependent Claim
38 words
The method of claim 2 wherein said junction is formed at a depth whereat the number of excess acceptor impurities in said p-type germanium is substantially equal to the number of excess donor impurities in said n-type germanium.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein said high purity p-type germanium is between approximately 1 × 10 10 and approximately 5 × 10 10 acceptors-cm -3 .
Claim 6
Dependent Claim
22 words
The method of claim 1 further including the step of fabricating said body to expose said p-type germanium and said n-type germanium.
Claim 7
Dependent Claim
25 words
The method of claim 5 wherein the body is a cylinder and the fabricating step comprises coring said cylinder whereby a coaxial structure is formed.
Claim 8
Dependent Claim
22 words
The method of claim 5 further including the step of forming electrical contacts on said p-type germanium and on said n-type germanium.
Claim 9
Dependent Claim
33 words
The method of claim 7 wherein said forming step comprises forming n + contacts by lithium diffusion on said n-type germanium and forming p + contacts by metal evaporation on said p-type germanium.
Claim 10
Dependent Claim
23 words
The method of claim 1 wherein said junction is formed at a depth greater than 1 mm from the surface of said body.
Claim 11
Independent Claim
67 words
A method for manufacturing deep junctions in a germanium body comprising: forming a body of high purity p-type germanium having an initial acceptor concentration and first diffusing lithium, from a precalculated concentration of lithium, deep into said body and subsequently diffusing lithium outward from the surface of said body, to form a junction of high purity p-type germanium and high purity n-type germanium deep within said body.
Claim 12
Independent Claim
67 words
A method for manufacturing deep junctions in a germanium body comprising: forming a body of high purity p-type germanium having an initial acceptor concentration and first diffusing lithium, from a precalculated concentration of lithium, deep into said body and subsequently diffusing lithium outward from the surface of said body, to form a junction of high purity p-type germanium and high purity n-type germanium deep within said body.
Claim 13
Dependent Claim
54 words
The method of claim 10 wherein the first diffusing step comprises immersing said body in a first molten alloy of lead and bismuth containing a predetermined low concentration of lithium, and the subsequent diffusion step comprises immersing said body in a second molten alloy of lead and bismuth which is substantially free of lithium.
Claim 14
Dependent Claim
22 words
The method of claim 11 wherein the diffusing step is performed at a temperature between approximately 400° C and approximately 600° C.
Claim 15
Dependent Claim
26 words
The method of claim 12 wherein said diffusing step further comprises monitoring the lithium concentration in said alloy by means of a voltage producing half cell.
Claim 16
Dependent Claim
22 words
The method of claim 13 wherein said half cell comprises a mixture of lithium, lead, and bismuth contained in a quartz bulb.
Claim 17
Dependent Claim
22 words
The method of claim 11 wherein said first alloy is formed by mixing a lithium-lead eutectic alloy with a lead-bismuth eutectic alloy.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-11-28 | 1981-05-30 | 1981-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-28 | 1985-05-30 | 1985-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-28 | 1989-05-30 | 1989-11-29 | $7700.00 | Window Closed / Lapsed |