Patent US3623818A successfully refreshed from Google Patents.
US3623818A
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Measurement of carrier concentration of semiconductor material
Assignee: International Business Machines Corp
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Filing: 1969-12-15
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Granted: 1971-11-30
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Expires: 1989-12-15
Abstract
Abstract Carrier concentration of a semiconductive material is measured by directing monochromatic light at the material. The light is polarized with its electric vector in the plane of incidence. The angle of incidence is varied until a minimum in reflectivity occurs. The angle at which the minimum occurs, referred to as the pseudo-Brewster angle theta B, is related to the carrier concentration, whence the carrier concentration may be determined by comparison with a series of standards or by calculation.
Inventors
- 👤 Edward E Gardner
- 👤 William A Keenan
- 👤 Paul A Schumann Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:23
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/26; G01R31/2607; G01R31/2637; G01N; G01N21/00; G01N21/17; G01N21/21; G01N21/55; G01N21/84; G01N2021/8461
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
64 words
The method according to claim 1 further including, where equilibrium carrier concentration is double-valued for a single angle of minimum reflectivity measuring the absolute intensity of the reflected beam (to determine which) at the angle of minimum reflectivity and correlating the aforementioned intensity measurement with said carrier concentration. (of two possible values of carrier concentration for a given angle of minimum reflectivity is correct.)
Claim 2
Dependent Claim
80 words
The method according to claim 1 further including, where equilibrium carrier concentration is double-valued for a single angle of minimum reflectivity, measuring the absolute intensity of the reflected beam at angles above and below the angle of minimum reflectivity (and determining the angular spread required to obtain the same magnitude of intensity at an angle above and below the angle of minimum reflectivity.) to obtain an angular spread measurement and correlating the aforementioned angular spread measurement with said carrier concentration.
Claim 3
Dependent Claim
52 words
The method according to claim 1 further including, where equilibrium carrier concentration is double-valued for a single angle of minimum reflectivity, measuring the absolute intensity of the reflected light polarized perpendicular to the plane of incidence at the angle of minimum reflectivity and correlating the aforementioned intensity measurement with said carrier concentration.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-29 | 1975-05-31 | 1975-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-29 | 1979-05-31 | 1979-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-29 | 1983-05-31 | 1983-11-30 | $7700.00 | Window Closed / Lapsed |