US4453127A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Determination of true electrical channel length of surface FET
Assignee: International Business Machines Corp
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Filing: 1982-06-09
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Granted: 1984-06-05
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Expires: 2002-06-09
Abstract
Abstract The true electrical channel length of a surface FET is determined by obtaining individual electron-beam-induced-current signal traces of source and drain junctions, thus eliminating the coupling effect of the two junctions. A reliable mask is formed as a function of the measured peak-to-peak distance subtracted by the depletion width.
Inventors
- 👤 Jerome D. Schick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:06
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/26; G01R31/265; G01R31/2653; G01R31/2607; G01R31/2621
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
153 words
A method for determining the electrical channel length of a surface field effect transistor, comprising the steps of: bevel sectioning said field effect transistor for exposing enlarged source and drain regions, connecting either one of the source or drain regions to the input of an electron-beam-induced-current detecting means with the other of the source or drain regions, and the substrate connected to a reference potential, line scanning the bevel section of said field effect transistor with an electron beam for obtaining a first scanning trace with said detecting means, changing the connections such that the other of said source or drain regions is connected to the input of said detecting means with said one of the source or drain regions, and the substrate connected to the reference potential, and line scanning said bevel section of said field effect transistor with the electron beam for obtaining a second scanning trace with said detecting means.
Claim 2
Independent Claim
153 words
A method for determining the electrical channel length of a surface field effect transistor, comprising the steps of: bevel sectioning said field effect transistor for exposing enlarged source and drain regions, connecting either one of the source or drain regions to the input of an electron-beam-induced-current detecting means with the other of the source or drain regions, and the substrate connected to a reference potential, line scanning the bevel section of said field effect transistor with an electron beam for obtaining a first scanning trace with said detecting means, changing the connections such that the other of said source or drain regions is connected to the input of said detecting means with said one of the source or drain regions, and the substrate connected to the reference potential, and line scanning said bevel section of said field effect transistor with the electron beam for obtaining a second scanning trace with said detecting means.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein said line scanning is made by a scanning electron microscope.
Claim 4
Dependent Claim
34 words
The method of claim 2 wherein said first and second scanning traces are manifested on a single plane preserving correlation with the position of the channel side portions of the source and drain junctions.
Claim 5
Dependent Claim
19 words
The method of claim 3 wherein said first and second scanning traces are double exposed on the same micrograph.
Claim 6
Dependent Claim
13 words
The method of claim 2 wherein said first and second traces are digitized.
Claim 7
Dependent Claim
16 words
The method of claim 2 wherein peak-to-peak distance between the first and second traces are measured.
Claim 8
Dependent Claim
38 words
The method of claim 6 wherein the depletion width corresponding to the portion of the depletion region of the junction on the channel side is subtracted from the measured peak-to-peak distance to give a true electrical channel length.
References Cited (Backward Citations)
US3531716A
Cited
US4296372A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-05 | 1987-12-05 | 1988-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-05 | 1991-12-05 | 1992-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-05 | 1995-12-05 | 1996-06-05 | $7700.00 | Window Closed / Lapsed |