Patent US5032786A successfully refreshed from Google Patents.
US5032786A
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Method of a measuring physical properties of buried channel
Assignee: Mitsubishi Electric Corp
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Filing: 1989-06-26
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Granted: 1991-07-16
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Expires: 2009-06-26
Abstract
Abstract Disclosed is a method of measuring physical properties of a buried channel, e.g., a generation current in a semiconductor substrate in which the buried channel is formed, a generation current of the surface of the semiconductor substrate, a channel potential and a surface potential of the buried channel. A gate ramp voltage is applied to a gate electrode formed over the buried channel and a current generated from a depletion layer at the buried channel and a gate current produced by changes in the capacitance of the buried channel are measured. The physical properties of the buried channel are obtained from the measured currents.
Inventors
- 👤 Mikihiro Kimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:00
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/282; G01R31/2831
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
128 words
A method of measuring physical properties of a buried channel layer of a second conductivity type disposed at a surface of a first conductivity type semiconductor substrate, an insulating film being disposed on the buried channel opposite the substrate, a gate electrode being disposed on said insulating film, comprising: while applying a reverse bias voltage across the buried channel and substrate, applying a gate ramp voltage to the gate electrode; simultaneously measuring, during application of the reverse bias and gate ramp voltages, a substrate current flowing between the substrate and the buried channel and a gate current flowing into the gate electrode; and calculating physical properties, such as channel potential, surface potential, and dopant impurity density distribution, of the buried channel from the measured substrate and gate currents.
Claim 2
Independent Claim
128 words
A method of measuring physical properties of a buried channel layer of a second conductivity type disposed at a surface of a first conductivity type semiconductor substrate, an insulating film being disposed on the buried channel opposite the substrate, a gate electrode being disposed on said insulating film, comprising: while applying a reverse bias voltage across the buried channel and substrate, applying a gate ramp voltage to the gate electrode; simultaneously measuring, during application of the reverse bias and gate ramp voltages, a substrate current flowing between the substrate and the buried channel and a gate current flowing into the gate electrode; and calculating physical properties, such as channel potential, surface potential, and dopant impurity density distribution, of the buried channel from the measured substrate and gate currents.
Claim 3
Dependent Claim
109 words
A method according to claim 1 wherein the buried channel includes second conductivity type contacts to which the reverse bias voltage is connected including calculating the surface potential φ s of the buried channel from: ##EQU3## where V R is the reverse bias voltage applied across the buried channel and substrate; V bi is a built-in potential between the buried channel and the contacts; V FB is a flat-band voltage of the buried channel; V PT is a punch-through voltage of the buried channel; C is a capacitance of the buried channel; C OX is a capacitance of the insulating film; and V G is the gate ramp voltage.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-07-15 | 1995-01-14 | 1995-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-15 | 1999-01-14 | 1999-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-15 | 2003-01-14 | 2003-07-16 | $7700.00 | Window Closed / Lapsed |