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US3887937A Expired / Lapsed US ⏱️ 0.0 years remaining

Semiconductor sensor

Assignee: Massachusetts Institute of Technology
•
Filing: 1972-09-21
•
Granted: 1975-06-03
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Expires: 1992-09-21
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Abstract

Abstract A semiconductor sensor adapted to detect with a high degree of sensitivity small magnitudes of a mechanical force, presence of traces of a gas or light. The sensor includes a high energy gap (i.e.,*1.0 electron volts) semiconductor wafer. Mechanical force is measured by employing a non-centrosymmetric material for the semiconductor. Distortion of the semiconductor by the force creates a contact potential difference (cpd) at the semiconductor surface, and this cpd is determined to give a measure of the force. When such a semiconductor is subjected to illumination with an energy less than the energy gap of the semiconductors, such illumination also creates a cpd at the surface. Detection of this cpd is employed to sense the illumination itself or, in a variation of the system, to detect a gas. When either a gas or light is to be detected and a crystal of a non-centrosymmetric material is employed, the presence of gas or light, in appropriate circumstances, results in a strain within the crystal which distorts the same and the distortion provides a mechanism for qualitative and quantitative evaluation of the gas or the light, as the case may be.

Inventors

  • 👤 Harry C Gatos
  • 👤 Jacek Lagowski

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 11:24
CPC Classifications
H; H10; H10N; H10N30/00; H10N30/30; B; B82; B82Y; B82Y15/00

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 106 words
A mechanical force sensor having, in combination, a thin noncentrosymmetric semiconductor wafer comprising a material having a high energy gap wherein the surface states are not in good communication with the bulk; means for applying the force to the wafer as a mechanical bending stress upon the wafer to effect changes in the population of the surface states of the semiconductor to effect changes in the surface barrier without appreciably affecting the electrical carrier concentration in the bulk material; and means for detecting the changes in the surface states as a consequence of said changes in population and for relating the same to the force to-be-sensed.
Claim 2
Dependent Claim 106 words
A mechanical force sensor having, in combination, a thin noncentrosymmetric semiconductor wafer comprising a material having a high energy gap wherein the surface states are not in good communication with the bulk; means for applying the force to the wafer as a mechanical bending stress upon the wafer to effect changes in the population of the surface states of the semiconductor to effect changes in the surface barrier without appreciably affecting the electrical carrier concentration in the bulk material; and means for detecting the changes in the surface states as a consequence of said changes in population and for relating the same to the force to-be-sensed.
Claim 3
Dependent Claim 106 words
A mechanical force sensor having, in combination, a thin non-centrosymmetric semiconductor wafer comprising a material having a high energy gap wherein the surface states are not in good communication with the bulk; means for applying the force to the wafer as a mechanical bending stress upon the wafer to effect changes in the population of the surface states of the semiconductor to effect changes in the surface barrier without appreciably affecting the electrical carrier concentration in the bulk material; and means for detecting the changes in the surface states as a consequence of said changes in population and for relating the same to the force to-be-sensed.
Claim 4
Dependent Claim 106 words
A mechanical force sensor having, in combination, a thin non-centrosymmetric semiconductor wafer comprising a material having a high energy gap wherein the surface states are not in good communication with the bulk; means for applying the force to the wafer as a mechanical bending stress upon the wafer to effect changes in the population of the surface states of the semiconductor to effect changes in the surface barrier without appreciably affecting the electrical carrier concentration in the bulk material; and means for detecting the changes in the surface states as a consequence of said changes in population and for relating the same to the force to-be-sensed.
Claim 5
Dependent Claim 33 words
A sensor as claimed in claim 1 in which the means for detecting comprises voltage sensing means which senses changes in the contact potential difference which occurs because of said changes in population.
Claim 6
Dependent Claim 28 words
A sensor as claimed in claim 1 in which the energy gap of the material of which the semiconductor is made is greater than about 1.0 electron volts.
Claim 7
Dependent Claim 28 words
A sensor as claimed in claim 3 in which the material of which the semiconductor is made is taken from the group consisting of CdS, ZnO and GaAs.
Claim 8
Dependent Claim 18 words
A sensor as claimed in claim 4 in which the semiconductor is a high-purity, n-type CdS single crystal.

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) 1978-06-02 1978-12-02 1979-06-03 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-06-02 1982-12-02 1983-06-03 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-06-02 1986-12-02 1987-06-03 $7700.00 Window Closed / Lapsed

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