US3697873A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for determining excess carrier lifetime in semiconductor devices
Assignee: Westinghouse Electric Corp
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Filing: 1969-05-28
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Granted: 1972-10-10
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Expires: 1989-05-28
Abstract
Abstract Described is a method for excess carrier lifetime testing of semiconductor materials by the use of ultrasonically soldered contacts in obtaining open-circuit voltage decay measurements. The method is particularly adapted for use in in-line production testing of semiconductor wafers and does not require the use of high temperatures to bond contacts to the wafer being tested.
Inventors
- 👤 Robert G Mazur
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:11
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/26; G01R31/2607; G01R31/2637
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
155 words
In the method for determining excess carrier lifetime in a semiconductor body of one conductivity type, the steps of diffusing into said body a region of the opposite conductivity type to form a P-N junction, ultrasonically depositing a mass of metal consisting of an alloy consisting of, by weight, 50 percent tin and 50 percent indium, onto opposed surfaces of said body, the body having an opposite type semiconductivity at said surfaces, heating each of said mass of metal to a temperature not exceeding 120* C while ultrasonically preventing the formation of metal oxides on the surfaces on the metal masses, thereby forming electrical contacts on said surfaces of said regions of opposed conductivity type, and connecting said contacts to a source of electrical current pulses whereby the voltage decay following the termination of each pulse applied across said electrodes is observed on an oscilloscope to determine the excess carrier lifetime in said semiconductor body.
Claim 2
Dependent Claim
155 words
In the method for determining excess carrier lifetime in a semiconductor body of one conductivity type, the steps of diffusing into said body a region of the opposite conductivity type to form a P-N junction, ultrasonically depositing a mass of metal consisting of an alloy consisting of, by weight, 50 percent tin and 50 percent indium, onto opposed surfaces of said body, the body having an opposite type semiconductivity at said surfaces, heating each of said mass of metal to a temperature not exceeding 120* C while ultrasonically preventing the formation of metal oxides on the surfaces on the metal masses, thereby forming electrical contacts on said surfaces of said regions of opposed conductivity type, and connecting said contacts to a source of electrical current pulses whereby the voltage decay following the termination of each pulse applied across said electrodes is observed on an oscilloscope to determine the excess carrier lifetime in said semiconductor body.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |