US4978915A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing semiconductor devices involving the detection of impurities
Assignee: Nokia Bell Labs
•
Filing: 1989-11-07
•
Granted: 1990-12-18
•
Expires: 2009-11-07
Abstract
Abstract The TVS method is a voltammetric method for detecting mobile ionic impurities in the dielectric layer of a MOS capacitor structure. Disclosed here is a method of semiconductor device fabrication involving a modified TVS method in which the voltage is changed in discrete steps rather than varied continuously, and charge, rather than induced current, is measured. The modified TVS method can be faster than conventional TVS, and calibration is unnecessary.
Inventors
- 👤 John M. Andrews, Jr.
- 👤 Nadia Lifshitz
- 👤 Gerald Smolinsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:07
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/01; G01R31/013; G01R31/016; G01R31/26; G01R31/2607; G01R31/2637; G01R31/2639
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
101 words
A method of semiconductor device fabrication including the step of detecting an impurity in a dielectric layer which is a part of the body such device, wherein the detecting step comprises: heating the body to an elevated temperature; applying a voltage across the dielectric layer; and varying the voltage between a maximum negative amplitude and a maximum positive amplitude; characterized in that the varying step comprises changing the voltage in discrete increments separated by time intervals, whereby a charge is induced by ionic impurity motion during each time interval; and the method further comprises the step of recording the induced charges.
Claim 2
Independent Claim
101 words
A method of semiconductor device fabrication including the step of detecting an impurity in a dielectric layer which is a part of the body such device, wherein the detecting step comprises: heating the body to an elevated temperature; applying a voltage across the dielectric layer; and varying the voltage between a maximum negative amplitude and a maximum positive amplitude; characterized in that the varying step comprises changing the voltage in discrete increments separated by time intervals, whereby a charge is induced by ionic impurity motion during each time interval; and the method further comprises the step of recording the induced charges.
Claim 3
Dependent Claim
40 words
The method of claim 1, wherein the maximum negative amplitude and the maximum positive amplitude are each adapted to create in the dielectric a volume-averaged electric field of at least about 1 MV/cm, but not more than about 3 MV/cm.
Claim 4
Dependent Claim
22 words
The method of claim 1, wherein the elevated temperature is at least about 100° C., but not more than about 400° C.
Claim 5
Dependent Claim
37 words
The method of claim 1, wherein the varying step comprises: increasing the voltage from the maximum negative amplitude to the maximum positive amplitude; and decreasing the voltage from the maximum positive amplitude to the maximum negative amplitude.
Claim 6
Dependent Claim
38 words
The method of claim 4, further comprising: before the increasing step, the step of stressing the dielectric layer at a negative voltage, and before the decreasing step, the step of stressing the dielectric layer at a positive voltage.
Claim 7
Dependent Claim
22 words
The method of claim 1, wherein the time intervals are at least about 0.1 second, but not more than about 10 seconds.
Claim 8
Dependent Claim
21 words
The method of claim 1, wherein the discrete voltage increments are at least 0.1 V., but not more than 5 V.
References Cited (Backward Citations)
US3995216A
Cited
US4282483A
Cited
US4323842A
Cited
US4319187A
Cited
US4325025A
Cited
US4611385A
Cited
US4661771A
Cited
US4758786A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-17 | 1994-06-18 | 1994-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-17 | 1998-06-18 | 1998-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-17 | 2002-06-18 | 2002-12-18 | $7700.00 | Window Closed / Lapsed |