US4606113A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing metal-semiconductor field effect transistors using orientation dependent etched recesses of different depths
Assignee: Qorvo US Inc
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Filing: 1985-03-25
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Granted: 1986-08-19
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Expires: 2005-03-25
Abstract
Abstract Field effect transistors are manufactured using a substrate of compound semiconductor material by defining two gate areas which have their longitudinal dimensions so oriented with respect to the crystal axes of the substrate that the substrate material is more readily etchable through one of the gate areas than through the other gate area. The semiconductor material is etched through both the gate areas simultaneously with the same etchant, whereby gate recesses of different respective depths are formed in the substrate. Metal is deposited into the recesses.
Inventors
- 👤 Ajit G. Rode
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:29
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/02; H10D84/05; H10D30/00; H10D30/80; H10D30/87; H10D62/00; H10D62/40; H10D62/405; H10D64/00; H10D64/01; H10D64/011; H10P; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/646; H10P50/648; H10D84/80; H10D84/82; H10D84/83; H10D84/84; H10D84/86; Y; Y10; Y10S; Y10S438/00; Y10S438/982
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
131 words
A method of manufacturing field effect transistors utilizing a substrate of monocrystralline compound semiconductor material having impurity ions implanted therein to a predetermined depth below a main surface of the substrate in at least two regions of the substrate, said method comprising defining two elongated gate areas of said main surface, over said two regions respectively, which gate areas have their longitudinal dimensions so oriented with respect to the crystal axes of the substrate that the substrate material is more readily etchable through one of said gate areas than through the other gate area, etching the semiconductor material through both said gate areas simultaneously with the same etchant, whereby recesses of different respective depths, each less than said predetermined depth, are formed in the substrate, and depositing metal into said recesses.
Claim 2
Independent Claim
131 words
A method of manufacturing field effect transistors utilizing a substrate of monocrystralline compound semiconductor material having impurity ions implanted therein to a predetermined depth below a main surface of the substrate in at least two regions of the substrate, said method comprising defining two elongated gate areas of said main surface, over said two regions respectively, which gate areas have their longitudinal dimensions so oriented with respect to the crystal axes of the substrate that the substrate material is more readily etchable through one of said gate areas than through the other gate area, etching the semiconductor material through both said gate areas simultaneously with the same etchant, whereby recesses of different respective depths, each less than said predetermined depth, are formed in the substrate, and depositing metal into said recesses.
Claim 3
Independent Claim
96 words
A method of manufacturing a device for controlling transfer of electrical charge within a substrate of monocrystalline compound semiconductor material, said method comprising defining two elongated areas of the surface of the substrate, which elongated areas have their longitudinal dimensions so oriented with respect to the crystal axes of the semiconductor material that the semiconductor material is more readily etchable through one of said areas than through the other area, and etching the semiconductor material through both said elongated areas simultaneously with the same etchant, whereby recesses of different respective depths are formed in the substrate.
Claim 4
Independent Claim
96 words
A method of manufacturing a device for controlling transfer of electrical charge within a substrate of monocrystalline compound semiconductor material, said method comprising defining two elongated areas of the surface of the substrate, which elongated areas have their longitudinal dimensions so oriented with respect to the crystal axes of the semiconductor material that the semiconductor material is more readily etchable through one of said areas than through the other area, and etching the semiconductor material through both said elongated areas simultaneously with the same etchant, whereby recesses of different respective depths are formed in the substrate.
Claim 5
Dependent Claim
24 words
A method according to claim 2, further comprising forming in each recess a structure for influencing the behavior of charge carriers within the substrate.
Claim 6
Dependent Claim
49 words
A method according to claim 2, wherein the substrate has impurity ions present therein to a predetermined depth below a main surface of the substrate, and said two elongated areas are both defined at said main surface and the depth of each recess is less than said predetermined depth.
Claim 7
Dependent Claim
57 words
A method according to claim 2, comprising, prior to defining said elongated areas, implanting impurity ions in the substrate to a predetermined depth below a main surface of the substrate in at least two discrete regions of the substrate, and wherein the two elongated areas are areas of said main surface, defined over said two regions respectively.
Claim 8
Dependent Claim
32 words
A method according to claim 3, wherein the step of forming in each recess a structure for influencing the behavior of charge carriers within the substrate comprises depositing metal into said recesses.
Claim 9
Dependent Claim
99 words
A method according to claim 5, wherein the step of implanting impurity ions in the substrate comprises a first implantation step in which impurity ions are implanted into the substrate to said predetermined depth in said two regions, and a second implantation step in which additional impurity ions are implanted into the substrate in first and second portions of each of said first and second regions, said first and second portions of each region being separated from each other by a third portion, and wherein the elongated areas are defined over said third portions of said two regions respectively.
Claim 10
Dependent Claim
35 words
A method according to claim 7, comprising establishing ohmic contact to each of said first and second regions and forming in each recess a structure for influencing the behavior of charge carriers in the substrate.
Claim 11
Dependent Claim
32 words
A method according to claim 8, wherein the step of forming in each recess a structure for influencing the behavior of charge carriers in the substrate comprises depositing metal into said recesses.
Claim 12
Dependent Claim
36 words
A method according to claim 8, further comprising establishing electrical connection between the ohmic contact made to the first portion of one region and the ohmic contact made to the first portion of the other region.
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) | 1989-08-18 | 1990-02-17 | 1990-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-18 | 1994-02-17 | 1994-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-18 | 1998-02-17 | 1998-08-19 | $7700.00 | Window Closed / Lapsed |