US3882391A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Testing the stability of MOSFET devices
Assignee: International Business Machines Corp
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Filing: 1973-06-25
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Granted: 1975-05-06
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Expires: 1993-06-25
Abstract
Abstract A method for testing the threshold stability of a MOSFET device including a phosphosilicate glass (PSG) thin film which covers the gate insulator to trap contaminants. The test comprises an electric field stress at ambient temperature for a short interval to determine polarization of the PSG film. The flat band potentials (VFB) measured before and after the stress period are used to determine whether the amount of PSG is sufficient to trap the contaminants present.
Inventors
- 👤 Robert E Liles
- 👤 Gerald D O'rourke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:40
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/316; G01R31/26; G01R31/2607; G01R31/2621
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
125 words
A method for determining the stability of semiconductor devices which include a phosphosilicate glass film on the surface thereof to trap contaminants comprising the steps of: measuring the initial flatband potential across said film; applying a fixed potential across said film for a duration sufficient to polarize said film and at a temperature insufficient to cause said contaminants to drift; remeasuring the flatband voltage to determine the polarization of said film; determining the amount of phosphosilicate glass in said film using the value of polarization; determining the amount of contaminants present using the value of said initial flatband potential and the value of said polarization; and comparing said determined amounts to insure that the amount of phosphosilicate glass is sufficient to trap the contaminants present.
Claim 2
Independent Claim
125 words
A method for determining the stability of semiconductor devices which include a phosphosilicate glass film on the surface thereof to trap contaminants comprising the steps of: measuring the initial flatband potential across said film; applying a fixed potential across said film for a duration sufficient to polarize said film and at a temperature insufficient to cause said contaminants to drift; remeasuring the flatband voltage to determine the polarization of said film; determining the amount of phosphosilicate glass in said film using the value of polarization; determining the amount of contaminants present using the value of said initial flatband potential and the value of said polarization; and comparing said determined amounts to insure that the amount of phosphosilicate glass is sufficient to trap the contaminants present.
Claim 3
Dependent Claim
18 words
A method as in claim 1 wherein said phosphosilicate glass film is disposed on a silicon dioxide insulator.
Claim 4
Dependent Claim
31 words
A method as in claim 1 wherein: said fixed potential is around 4.3 X 106 volts per centimeter; said temperature is at room ambient; and said duration is around two minutes.
Claim 5
Dependent Claim
29 words
A method as in claim 3 wherein the combined thickness of said phosphosilicate glass film and said silicon dioxide insulator is 700A and said fixed potential is 30 volts.
Claim 6
Dependent Claim
46 words
A method as in claim 2 wherein said phosphosilicate glass film and said silicon dioxide insulator are fabricated in the kerf area of a semiconductor wafer containing integrated circuit arrays of MOSFET devices and said method is an indicator for the reliability of said MOSFET devices.
Claim 7
Independent Claim
102 words
A method for testing the stability of the threshold voltage of field effect transistors which include a phosphosilicate glass film as a gate insulator comprising the steps of: measuring the initial flatband potential across said film; applying a fixed potential across said film at ambient temperatures for a duration sufficient to polarize said film; remeasuring the flatband voltage after said potential application to determine the polarization of said film; and determining from the measured values of said initial flatband potential and said polarization whether there is sufficient phosphosilicate glass available to trap contaminants present on the surface of said field effect transistors.
Claim 8
Independent Claim
102 words
A method for testing the stability of the threshold voltage of field effect transistors which include a phosphosilicate glass film as a gate insulator comprising the steps of: measuring the initial flatband potential across said film; applying a fixed potential across said film at ambient temperatures for a duration sufficient to polarize said film; remeasuring the flatband voltage after said potential application to determine the polarization of said film; and determining from the measured values of said initial flatband potential and said polarization whether there is sufficient phosphosilicate glass available to trap contaminants present on the surface of said field effect transistors.
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) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |