US3898359A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin film magneto-resistors and methods of making same
Assignee: PRECISION ELECTRONIC COMPONENT
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Filing: 1974-01-15
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Granted: 1975-08-05
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Expires: 1994-01-15
Abstract
Abstract Thin film magneto-resistors are made by applying to an electrically insulating substrate, for example glass or alumina, a thin coating of chromium or nickel, depositing on said coating a layer of elemental antimony or arsenic, and a layer of indium, the ratio of the mass of the antimony or arsenic layer to the mass of the indium layer being equal to the ratio of their atomic weights. Said layers are then caused to combine chemically to form a stoichiometric polycrystalline indium antimonide or indium arsenide compound semiconductor. The semiconductor is then covered with an indium coating, indium strips are formed by etching the indium coating, and then parts of the semiconductor and coatings are removed to achieve a desired electrical resistance.
Inventors
- 👤 Gajanan Shivarao Nadkarni
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:58
CPC Classifications
H; H10; H10N; H10N50/00; H10N50/10; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24917; Y10T428/24926
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
141 words
THE METHOD OF MAKING A THIN FILM MAGNETO-RESISTOR, COMPRISING DEPOSITING AN ELECTRICALLY CONDUCTIVE COATING ON A SUBSTRATE PROVIDING INSULATION BENEATH THE COATING, DEPOSITING A LAYER OF ELEMENTAL ANTIMONY OR ARSENIC AND A LAYER OF ELEMENTAL INDIUM ONE UPON THE OTHER ON THE CONDUCTIVE COATING, THE RATIO OF THE MASS OF THE ANTIMONY OR ARSENIC LAYER TO THE MASS OF THE INDIUM LAYER BEING EQUAL TO THE RATIO OF THEIR ATOMIC WEIGHTS, AND HEATING THE LAYERS TO CAUSE THEM TO COMBINE THERMOCHEMICALLY TO FORM A STOICHIOMETRIC POLYCRYSTALLINE INDIUM ANTIMONIDE OR INDIUM ARSENIDE SEMI-CONDUCTOR LAYER, THE THICKNESSES OF THE ANTIMONY OR ARSENIC AND INDIUM LAYERS AND OF THE CONDUCTIVE COATING BEING SELECTED SO THAT THE RESISTANCE OF THE LATTER IS MUCH HIGHER THAN THAT OF THE SEMICONDUCTOR LAYER, AND THE SUBSTRATE BEING CAPABLE OF WITHSTANDING THE HEATING REQUIRED TO COMBINE THE ELEMENTAL LAYERS.
Claim 2
Independent Claim
141 words
THE METHOD OF MAKING A THIN FILM MAGNETO-RESISTOR, COMPRISING DEPOSITING AN ELECTRICALLY CONDUCTIVE COATING ON A SUBSTRATE PROVIDING INSULATION BENEATH THE COATING, DEPOSITING A LAYER OF ELEMENTAL ANTIMONY OR ARSENIC AND A LAYER OF ELEMENTAL INDIUM ONE UPON THE OTHER ON THE CONDUCTIVE COATING, THE RATIO OF THE MASS OF THE ANTIMONY OR ARSENIC LAYER TO THE MASS OF THE INDIUM LAYER BEING EQUAL TO THE RATIO OF THEIR ATOMIC WEIGHTS, AND HEATING THE LAYERS TO CAUSE THEM TO COMBINE THERMOCHEMICALLY TO FORM A STOICHIOMETRIC POLYCRYSTALLINE INDIUM ANTIMONIDE OR INDIUM ARSENIDE SEMI-CONDUCTOR LAYER, THE THICKNESSES OF THE ANTIMONY OR ARSENIC AND INDIUM LAYERS AND OF THE CONDUCTIVE COATING BEING SELECTED SO THAT THE RESISTANCE OF THE LATTER IS MUCH HIGHER THAN THAT OF THE SEMICONDUCTOR LAYER, AND THE SUBSTRATE BEING CAPABLE OF WITHSTANDING THE HEATING REQUIRED TO COMBINE THE ELEMENTAL LAYERS.
Claim 3
Dependent Claim
18 words
The method claimed in claim 1 wherein the total thickness of the layers is at least 4 microns.
Claim 4
Dependent Claim
14 words
The method claimed in claim 1 wherein the substrate comprises an amorphous electrical insulator.
Claim 5
Dependent Claim
22 words
The method claimed in claim 1 wherein the substrate incorporates magnetic material and provides insulation between the magnetic material and the semi-conductor.
Claim 6
Dependent Claim
18 words
The method claimed in claim 1 wherein the coating and the elemental layers are formed by vacuum deposition.
Claim 7
Dependent Claim
24 words
The method claimed in claim 5 wherein, before said coating and said layers are formed, the substrate is de-gassed by heating under low pressure.
Claim 8
Dependent Claim
17 words
The method claimed in claim 6 wherein said low pressure is about 10 6 Torr or lower.
Claim 9
Dependent Claim
20 words
The method claimed in claim 5 wherein the layers are combined by heating in an inert gas above atmospheric pressure.
Claim 10
Dependent Claim
19 words
The method claimed in claim 8 wherein the layers are heated to about 550*C and then allowed to cool.
Claim 11
Dependent Claim
21 words
The method claimed in claim 5 wherein the electrically conductive coating is a chromium coating less that 1,000 A units thick.
Claim 12
Dependent Claim
31 words
The method claimed in claim 10 wherein an antimony or arsenic layer is formed on the chromium coating, and the indium layer is then formed on the antimony or arsenic layer.
Claim 13
Dependent Claim
22 words
The method claimed in claim 1 wherein electrically conductive strips are formed on a surface of the semi-conductor remote from the substrate.
Claim 14
Dependent Claim
48 words
The method claimed in claim 12 wherein parts of the semi-conductor are removed to provide through the semi-conductor a current path of desired resistance, parts of said coating and of said strips being also removed, the remaining parts of the strips being generally perpendicular to said current path.
Claim 15
Dependent Claim
12 words
The method claimed in claim 12 wherein said strips are indium strips.
Claim 16
Dependent Claim
29 words
The method claimed in claim 14 wherein the indium strips are formed by applying a coating of indium to said surface, and then etching away parts of the indium.
Claim 17
Dependent Claim
15 words
The method claimed in claim 15 wherein the indium strips are about 2500 A thick.
Claim 18
Dependent Claim
19 words
The method claimed in claim 15 wherein the coating of indium is formed on the semiconductor under low pressure.
Claim 19
Dependent Claim
56 words
A THIN FILM MAGNETO-RESOSTOR, COMPRISING A HEAT RESISTANT SUBSTRATE, A CURRENT PATH DEFINED BY A SEMI-CONDUCTOR LAYER OF POLYCRYSTALLINE INDIUM ANTIMONIDE OR INDIUM ARSENIDE, AND AN ELECTRICALLY CONDUCTIVE COATING BONDING THE SEMI-CONDUCTOR LAYER TO AN INSULATING LAYER FORMED BY THE SUBSTRATE, THE ELECTRICAL RESISTANCE OF THE COATING BEING MUCH HIGHER THAN THAT OF THE SEMI-CONDUCTOR LAYER.
Claim 20
Dependent Claim
56 words
A THIN FILM MAGNETO-RESOSTOR, COMPRISING A HEAT RESISTANT SUBSTRATE, A CURRENT PATH DEFINED BY A SEMI-CONDUCTOR LAYER OF POLYCRYSTALLINE INDIUM ANTIMONIDE OR INDIUM ARSENIDE, AND AN ELECTRICALLY CONDUCTIVE COATING BONDING THE SEMI-CONDUCTOR LAYER TO AN INSULATING LAYER FORMED BY THE SUBSTRATE, THE ELECTRICAL RESISTANCE OF THE COATING BEING MUCH HIGHER THAN THAT OF THE SEMI-CONDUCTOR LAYER.
Claim 21
Dependent Claim
18 words
A magneto-resistor according to claim 18, wherein magnetic material is incorporated in the substrate beneatH said insulating layer.
Claim 22
Dependent Claim
32 words
A magneto-resistor according to claim 18, further comprising electrically conductive strips bonded to that surface of the semi-conductor layer remote from the substrate, said strips extending generally transversely of the current path.
Claim 23
Dependent Claim
14 words
A magneto-resistor as claimed in claim 20 wherein the electrically conductive coating is chromium.
Claim 24
Dependent Claim
29 words
A magneto-resistor as claimed in claim 21 wherein the intermediate coating is less than 1,000 A units thick and the electrically conductive strips are about 2,500 A units thick.
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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) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |