US3851379A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid state components
Assignee: Westinghouse Electric Corp
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Filing: 1973-05-16
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Granted: 1974-12-03
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Expires: 1993-05-16
Abstract
Abstract There is disclosed a method of making a metal-oxide silicon field-effect transistor (MOSFET) capable of delivering substantial power (5 to 10 watts) in the microwave frequency range (about 5 Gigahertz) and operating as an amplifier over a wide bandwidth through a reasonably high input impedance exceeding about 5 ohms. The method is practiced with a layered blank of silicon having, say, an N+ substrate on which is a Player; there is a second N+ layer on the P-layer. Regions, each having a surface for deposit of a drain, are prepared on the second layer. Grooves are etched undercutting these regions so that they overhang the grooves. The gate and drain electrodes are deposited simultaneously by linear beams of vapor at supplementary angles to the prepared surfaces. The angles and the length of the overhangs are such that the gate electrodes extend only along the projections of the edges of the contiguous Players which extend along the groove, minimizing the capacitance between the gate electrode and the other electrodes. There is also disclosed a MOSFET produced in the practice of this invention.
Inventors
- 👤 P Gutknecht
- 👤 T Heng
- 👤 H Nathanson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:49
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/63; H10P; H10P95/00; H10D64/00; H10D64/20; H10D64/27; H10D64/311; H10D64/411; H10D64/511; H10D64/512; H10D64/513; Y; Y10; Y10S; Y10S148/00; Y10S148/143
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
235 words
The method of producing from a blank a field-effect transistor (FET), capable of operating at microwave frequencies and of handling substantial power at said frequencies, the said blank having a substrate doped with carriers of a first polarity and having a first layer thereon doped with carriers of opposite polarity, said first layer having a second layer thereon doped with carriers of said first polarity, the said method comprising preparing on said second layer a pair of spaced regions, at least one of said regions having a surface for deposit thereon of a drain electrode, forming a groove in said blank between said prepared regions, each of said regions overhanging said groove a predetermined distance, said groove penetrating to said substrate, depositing a coating of an electrically insulating material on the surface of said groove, depositing a gate electrode on said coating by projecting, on the part of said coating under said one region, a linear beam of a metal vapor at an angle to said surface from that direction of the region of the pair other than said one region and permitting said vapor to solidify, adjacent to and under the overhang of said one region, said beam being shadowed by said overhangs of said regions so that said gate electrode is deposited substantially only opposite the edge of said first layer extending along said groove; and depositing said drain electrode on said surface.
Claim 2
Independent Claim
235 words
The method of producing from a blank a field-effect transistor (FET), capable of operating at microwave frequencies and of handling substantial power at said frequencies, the said blank having a substrate doped with carriers of a first polarity and having a first layer thereon doped with carriers of opposite polarity, said first layer having a second layer thereon doped with carriers of said first polarity, the said method comprising preparing on said second layer a pair of spaced regions, at least one of said regions having a surface for deposit thereon of a drain electrode, forming a groove in said blank between said prepared regions, each of said regions overhanging said groove a predetermined distance, said groove penetrating to said substrate, depositing a coating of an electrically insulating material on the surface of said groove, depositing a gate electrode on said coating by projecting, on the part of said coating under said one region, a linear beam of a metal vapor at an angle to said surface from that direction of the region of the pair other than said one region and permitting said vapor to solidify, adjacent to and under the overhang of said one region, said beam being shadowed by said overhangs of said regions so that said gate electrode is deposited substantially only opposite the edge of said first layer extending along said groove; and depositing said drain electrode on said surface.
Claim 3
Dependent Claim
345 words
The method of claim 1 for producing a metal-oxide silicon field-effect transistor (MOSFET) from a blank including a substrate of silicon doped with carriers of a first polarity having thereon a first layer of silicon doped with carriers of opposite polarity, said second layer having thereon a layer of silicon doped with carriers of said first polarity, the said method including the steps: a. depositing a coating of silicon dioxide on said second layer; b. removing the silicon dioxide from selected areas of said second layer leaving at least a first pair of strips of silicon dioxide and a second pair of strips of silicon dioxide, strips of exposed second layer extending between the dioxide strips of each pair and between said pairs; c. depositing a coating of silicon nitride on said second layer and on said pairs of strips of said dioxide; d. depositing a coating of silicon dioxide throughout on said coating of silicon nitride; e. masking the silicon dioxide coating between the strips of each pair and removing the exposed silicon dioxide and silicon nitride; f. producing a groove between the adjacent strips of dioxide of the pairs by removing the material between the pairs of strips of dioxide down to the substrate, undercutting the adjacent strips of dioxide of the pairs so that said adjacent strips overhang the groove followed by oxidation of exposed silicon to produce a coating of silicon dioxide; g. removing the silicon nitride from the oxide strips; h. depositing an electrically conductive coating on the strips of each pair and on the portion of the second layer between the strips of each pair thus forming the drain electrodes; and j. projecting the linear beam of a metal vapor at an angle to the surfaces of at least one pair of said strips to form the gate electrode within the groove adjacent the other set of said strips, said beam being shadowed by the overhangs of said strips so that said gate electrode is deposited substantially only opposite the edge of said first layEr extending along said groove.
Claim 4
Dependent Claim
22 words
The method of claim 1 wherein the linear beam of metal vapor, which deposits the gate electrode, simultaneously deposits the drain electrode.
Claim 5
Dependent Claim
21 words
The method of claim 2 wherein the linear beam of metal which deposits the gate electrode simultaneously deposits the drain electrode.
Claim 6
Dependent Claim
139 words
The method of claim 1 wherein a plurality of spaced regions are prepared on said second layer, each region having a surface for deposit of a drain electrode, and wherein a plurality of grooves are formed between the adjacent ends of successive pairs of spaced regions, each groove being overhung a predetermined distance by the spaced regions between which it is formed, and wherein the linear beam of vapor is first projected at an angle theta to the surfaces of said regions to deposit gate electrodes under the alternate overhangs which extends towards the direction from which the beam is projected and thereafter the beam is projected at an angle of about 180*- theta to the surfaces of said regions to deposit gate electrodes under the alternate overhangs which extend towards the direction from which the last-named beam projects.
Claim 7
Dependent Claim
27 words
The method of claim 5 wherein the linear beams deposit the drain electrodes simultaneously with the gate electrodes whereby the drain electrodes are of low electrical conductivity.
Claim 8
Independent Claim
241 words
The method of producing from a blank a field-effect transistor capable of operating at microwave frequencies and of handling substantial power at said frequencies, the said blank including a first layer doped with carriers of a first polarity said first layer being interposed between an upper layer and a lower layer, said upper and lower layers being doped with carriers of opposite polarity, the said method comprising preparing on said upper layer of a pair of spaced regions, at least one of said regions having a surface for deposit therein of a drain electrode, forming a groove in said blank between said prepared regions, said groove extending between said regions, each of said regions overhanging said groove a predetermined distance, depositing a coating of an electrically insulating material on the surface of said groove, depositing a gate electrode on said coating by projecting, on the part of said coating under said one region, a linear beam of a metal vapor at an angle to said surface from the direction of that region of the pair of spaced regions other than said one region, and permitting said vapor to solidify, adjacent to and under the overhang of said one region, said beam being shadowed by said overhangs of said regions so that said gate electrode is deposited substantially only opposite the edge of said first layer extending along said groove; and depositing said drain electrode on the surface of said one region.
Claim 9
Independent Claim
241 words
The method of producing from a blank a field-effect transistor capable of operating at microwave frequencies and of handling substantial power at said frequencies, the said blank including a first layer doped with carriers of a first polarity said first layer being interposed between an upper layer and a lower layer, said upper and lower layers being doped with carriers of opposite polarity, the said method comprising preparing on said upper layer of a pair of spaced regions, at least one of said regions having a surface for deposit therein of a drain electrode, forming a groove in said blank between said prepared regions, said groove extending between said regions, each of said regions overhanging said groove a predetermined distance, depositing a coating of an electrically insulating material on the surface of said groove, depositing a gate electrode on said coating by projecting, on the part of said coating under said one region, a linear beam of a metal vapor at an angle to said surface from the direction of that region of the pair of spaced regions other than said one region, and permitting said vapor to solidify, adjacent to and under the overhang of said one region, said beam being shadowed by said overhangs of said regions so that said gate electrode is deposited substantially only opposite the edge of said first layer extending along said groove; and depositing said drain electrode on the surface of said one region.
Claim 10
Independent Claim
352 words
The method of producing, from a blank, a field-effect transistor capable of operating at microwave frequencies and of handling substantial power at said frequencies, the said blank including a first layer doped with carriers of a first polarity, said first layer being interposed between an upper layer and a lower layer, said upper and lower layers being doped with carriers of opposite polarity, the said method comprising, preparing on said upper layer a plurality of spaced regions, certain of said regions having surfaces thereon for deposit of drain electrodes, forming a groove each between successive of said spaced regions, each said groove penetrating at least through said first layer, each said groove being overhung (a) at least on one side by the surface of said region defining said last-named groove, (b) the grooves between successive layers merging at one end of said blank in a common depression generally transverse to said grooves, depositing a coating of electrically insulating material on the surface of each said groove, said coating extending over said first layer penetrating into said groove, depositing a gate electrode on said coating in said grooves by projecting on the surface of said blAnk a linear beam of a metal vapor at an angle to said surface from the direction opposite to said overhang (c) of each said groove, said beam penetrating under said (d) overhang on said one side of each said groove and depositing on the said coating under said overhang, and permitting said projected vapor on said coating to solidify, said vapor when depositing into each said groove being shadowed by said (e) overhang on one side and by the boundary of said last-named groove on the opposite side (f) so that the gate electrode under the overhang of said last-named groove is deposited substantially only on the coating opposite the edge of said first layer extending along said last-named groove; while depositing said gate electrodes also depositing said vapor in said depression and permitting said vapor in said depression to solidify, thereby providing an interconnecting terminal for said gates; and depositing said drain electrodes on said surface.
Claim 11
Independent Claim
352 words
The method of producing, from a blank, a field-effect transistor capable of operating at microwave frequencies and of handling substantial power at said frequencies, the said blank including a first layer doped with carriers of a first polarity, said first layer being interposed between an upper layer and a lower layer, said upper and lower layers being doped with carriers of opposite polarity, the said method comprising, preparing on said upper layer a plurality of spaced regions, certain of said regions having surfaces thereon for deposit of drain electrodes, forming a groove each between successive of said spaced regions, each said groove penetrating at least through said first layer, each said groove being overhung (a) at least on one side by the surface of said region defining said last-named groove, (b) the grooves between successive layers merging at one end of said blank in a common depression generally transverse to said grooves, depositing a coating of electrically insulating material on the surface of each said groove, said coating extending over said first layer penetrating into said groove, depositing a gate electrode on said coating in said grooves by projecting on the surface of said blAnk a linear beam of a metal vapor at an angle to said surface from the direction opposite to said overhang (c) of each said groove, said beam penetrating under said (d) overhang on said one side of each said groove and depositing on the said coating under said overhang, and permitting said projected vapor on said coating to solidify, said vapor when depositing into each said groove being shadowed by said (e) overhang on one side and by the boundary of said last-named groove on the opposite side (f) so that the gate electrode under the overhang of said last-named groove is deposited substantially only on the coating opposite the edge of said first layer extending along said last-named groove; while depositing said gate electrodes also depositing said vapor in said depression and permitting said vapor in said depression to solidify, thereby providing an interconnecting terminal for said gates; and depositing said drain electrodes on said surface.
Claim 12
Independent Claim
348 words
The method of producing, from a blank, a field-effect transistor capable of operating at microwave frequencies and of handling substantial power at said frequencies, the said blank including a first layer doped with carriers of a first polarity, said first layer being interposed between an upper layer and a lower layer, said upper and lower layers being doped with carriers of opposite polarity, the said method comprising, preparing on said upper layer a plurality of spaced regions, certain of said regions having surfaces thereon for deposit of drain electrodes, forming a groove each between successive of said spaced regions, each said groove penetrating at least through said first layer, each said groove being overhung (a) on both sides by the surface of the region defining, said last-named groove, (b) the grooves between successive layers merging at one end of said blank in a common depression generally transverse to said grooves, depositing a coating of electrically insulating material on the surface of each said groove, said coating extending over said first layer penetrating into said groove, depositing a gate electrode on said coating in said grooves by projecting on the surface of said blank a linear beam of a metal vapor at an angle to said surface from the direction opposite to said overhang (c) at least on one side of each said groove, said beam penetrating under said (d) last-named overhang on said one side of each said groove and depositing on the said coating under said overhang, and permitting said projected vapor in said coating to solidify, said vapor when depositing into each said groove being shadowed by said (e) overhangs on both sides of said last-named groove (f) so that the gate electrode under the overhang of said last-named groove is deposited substantially only in the coating opposite the edge of said first layer extending along said last-named groove; while depositing said gate electrodes also depositing said vapor in said depression and permitting said vapor in said depression to solidify, thereby providing an interconnecting terminal for said gates; and depositing said drain electrodes on said surface.
Claim 13
Independent Claim
348 words
The method of producing, from a blank, a field-effect transistor capable of operating at microwave frequencies and of handling substantial power at said frequencies, the said blank including a first layer doped with carriers of a first polarity, said first layer being interposed between an upper layer and a lower layer, said upper and lower layers being doped with carriers of opposite polarity, the said method comprising, preparing on said upper layer a plurality of spaced regions, certain of said regions having surfaces thereon for deposit of drain electrodes, forming a groove each between successive of said spaced regions, each said groove penetrating at least through said first layer, each said groove being overhung (a) on both sides by the surface of the region defining, said last-named groove, (b) the grooves between successive layers merging at one end of said blank in a common depression generally transverse to said grooves, depositing a coating of electrically insulating material on the surface of each said groove, said coating extending over said first layer penetrating into said groove, depositing a gate electrode on said coating in said grooves by projecting on the surface of said blank a linear beam of a metal vapor at an angle to said surface from the direction opposite to said overhang (c) at least on one side of each said groove, said beam penetrating under said (d) last-named overhang on said one side of each said groove and depositing on the said coating under said overhang, and permitting said projected vapor in said coating to solidify, said vapor when depositing into each said groove being shadowed by said (e) overhangs on both sides of said last-named groove (f) so that the gate electrode under the overhang of said last-named groove is deposited substantially only in the coating opposite the edge of said first layer extending along said last-named groove; while depositing said gate electrodes also depositing said vapor in said depression and permitting said vapor in said depression to solidify, thereby providing an interconnecting terminal for said gates; and depositing said drain electrodes on said surface.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |