US5770525A
Expired / Lapsed
US
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Method of fabricating semiconductor device and method of fabricating high-frequency semiconductor device
Assignee: Honda Motor Co Ltd
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Filing: 1995-11-16
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Granted: 1998-06-23
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Expires: 2015-11-16
Abstract
Abstract A superlattice buffer layer, an AlGaAs layer, an InGaAs layer, an AlGaAs layer, and an N+GaAs layer are successively deposited on a GaAs layer by epitaxial growth. Using an electron-beam resist as a mask, a patterning layer in the form of an SiO2 film is formed on the N+GaAs layer. Then, only the N+GaAs layer is selectively etched through an opening in the electron-beam resist with a water-diluted etchant which comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:4000, thereby forming a recess in the N+GaAs layer. Using the electron-beam resist also as a mask, a gate metal member serving as the base end of a T-shaped gate electrode is deposited on the AlGaAs layer in the recess. The width of an opening in the electron-beam resist determines the gate length.
Inventors
- 👤 Tomoyuki Kamiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:15
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/015; H10D64/00; H10D64/01; H10D64/012; H10D64/0124; H10D64/0125; H10P; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/646; H10P50/69; H10P50/691; H10P50/692
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
112 words
A method of fabricating a semiconductor device having a heterojunction structure between an AlGaAs layer and a GaAs layer disposed thereon, comprising the steps of: forming a resist having an opening which has a width of at most 0.5 mm on the GaAs layer; selectively etching only the GaAs layer through said opening with an etchant which comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:4000, said mixture being diluted with water, thereby to form a recess in said GaAs layer; and forming an electrode on the AlGaAs layer in said recess through said opening, using said resist as a mask.
Claim 2
Independent Claim
112 words
A method of fabricating a semiconductor device having a heterojunction structure between an AlGaAs layer and a GaAs layer disposed thereon, comprising the steps of: forming a resist having an opening which has a width of at most 0.5 mm on the GaAs layer; selectively etching only the GaAs layer through said opening with an etchant which comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:4000, said mixture being diluted with water, thereby to form a recess in said GaAs layer; and forming an electrode on the AlGaAs layer in said recess through said opening, using said resist as a mask.
Claim 3
Dependent Claim
33 words
A method according to claim 1, further comprising the step of: applying a surface-active agent before said GaAs layer is selectively etched, for thereby allowing the etchant to enter easily into said opening.
Claim 4
Dependent Claim
21 words
A method according to claim 1, wherein said mixture is diluted with at least about six times its volume of water.
Claim 5
Dependent Claim
29 words
A method according to claim 1, wherein said etchant comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:8000.
Claim 6
Dependent Claim
16 words
A method according to claim 1, wherein said opening has a width of about 0.1 mm.
Claim 7
Independent Claim
62 words
A method of fabricating a high-frequency semiconductor device having a heterojunction between an AlGaAs layer having a thickness of about 300 angstroms and a GaAs layer disposed adjacent thereto, comprising the step of: selectively etching the GaAs layer with an etchant which comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:4000.
Claim 8
Independent Claim
62 words
A method of fabricating a high-frequency semiconductor device having a heterojunction between an AlGaAs layer having a thickness of about 300 angstroms and a GaAs layer disposed adjacent thereto, comprising the step of: selectively etching the GaAs layer with an etchant which comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:4000.
Claim 9
Dependent Claim
21 words
A method according to claim 6, wherein said mixture is diluted with at least about six times its volume of water.
Claim 10
Dependent Claim
29 words
A method according to claim 6, wherein said etchant comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:8000.
Claim 11
Independent Claim
80 words
A method of fabricating a high-frequency semiconductor device having a heterojunction between an AlGaAs layer in which a mixed-crystal ratio of Al ranges from 0.2 to 0.3 and which has a thickness of about 300 angstroms and a GaAs layer disposed adjacent to the AlGaAs layer, comprising the step of: selectively etching only the GaAs layer with an etchant which comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:4000.
Claim 12
Independent Claim
80 words
A method of fabricating a high-frequency semiconductor device having a heterojunction between an AlGaAs layer in which a mixed-crystal ratio of Al ranges from 0.2 to 0.3 and which has a thickness of about 300 angstroms and a GaAs layer disposed adjacent to the AlGaAs layer, comprising the step of: selectively etching only the GaAs layer with an etchant which comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:4000.
Claim 13
Dependent Claim
21 words
A method according to claim 9, wherein said mixture is diluted with at least about six times its volume of water.
Claim 14
Dependent Claim
29 words
A method according to claim 9, wherein said etchant comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:8000.
Claim 15
Independent Claim
67 words
A method of fabricating a high-frequency semiconductor device having a heterojunction between an AlGaAs layer and a GaAs layer, comprising the step of: selectively etching only the GaAs layer with an etchant which comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:4000, said mixture being diluted with at least about six times its volume of water.
Claim 16
Independent Claim
67 words
A method of fabricating a high-frequency semiconductor device having a heterojunction between an AlGaAs layer and a GaAs layer, comprising the step of: selectively etching only the GaAs layer with an etchant which comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:4000, said mixture being diluted with at least about six times its volume of water.
Claim 17
Dependent Claim
29 words
A method according to claim 12, wherein said etchant comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:8000.
Claim 18
Independent Claim
55 words
A method of fabricating a semiconductor device having a heterojunction structure between an AlGaAs layer and a GaAs layer disposed thereon, comprising the step of: selectively etching only the GaAs layer with an etchant which comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:8000.
Claim 19
Independent Claim
55 words
A method of fabricating a semiconductor device having a heterojunction structure between an AlGaAs layer and a GaAs layer disposed thereon, comprising the step of: selectively etching only the GaAs layer with an etchant which comprises a mixture of ammonia water and hydrogen peroxide solution which are mixed at a ratio of at least 1:8000.
Claim 20
Dependent Claim
21 words
A method according to claim 14, wherein said mixture is diluted with at least about six times its volume of water.
References Cited (Backward Citations)
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