EP0602671A2
Expired / Lapsed
EP
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Heterojunction field effect transistor having an improved transistor characteristic
Assignee: NEC Corp
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Filing: 1993-12-17
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Granted: —
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Expires: 2013-12-17
Abstract
Abstract A field effect transistor (20) comprises a first semiconductor layer (24) and a second semiconductor layer (25) formed on the first semiconductor layer. The first semiconductor layer is an undoped layer and is composed of InGaAs. The second semiconductor layer is composed of InAlGaP and is a doped layer in which an n-type impurity is doped. A heterojunction structure is formed between the first semiconductor layer and the second semiconductor layer.
Inventors
- 👤 Kenichi Maruhashi
- 👤 Kazuhiko Onda
- 👤 Masaaki Kuzuhara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 01:36
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/40; H10D30/47; H10D30/471; H10D30/473; H10D30/4732
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
52 words
A field effect transistor comprising a first semiconductor layer, a second semiconductor layer formed on said first semiconductor layer, and a heterojunction structure formed between said first semiconductor layer and said second semiconductor layer, wherein: said first semiconductor layer is composed of InGaAs; and said second semiconductor layer being composed of InAlGaP.
Claim 2
Dependent Claim
38 words
A field effect transistor as claimed in Claim 1, wherein: said first semiconductor layer is an undoped semiconductor layer; and said second semiconductor layer being further composed of an impurity which is doped in said second semiconductor layer.
Claim 3
Dependent Claim
16 words
A field effect transistor as claimed in Claim 2, wherein said impurity is an n-type impurity.
Claim 4
Dependent Claim
24 words
A field effect transistor as claimed in Claim 3, wherein said impurity is one selected from the group consisting of silicon, sulfur, and selenium.
Claim 5
Dependent Claim
48 words
A field effect transistor as claimed in Claim 3, wherein said first semiconductor layer comprises: an undoped film; and a doped film in which a first impurity is doped; said second semiconductor layer being further composed of a second impurity which is doped in said second semiconductor layer.
Claim 6
Dependent Claim
22 words
A field effect transistor as claimed in Claim 5, wherein each of said first and said second impurities is an n-type impurity.
Claim 7
Dependent Claim
30 words
A field effect transistor as claimed in Claim 6, wherein each of said first and said second impurities is one selected from the group consisting of silicon, sulfur, and selenium.
Claim 8
Dependent Claim
39 words
A field effect transistor as claimed in Claim 3, further comprising a semi-insulating substrate and a buffer layer formed on said semi-insulating substrate, wherein said first semiconductor layer is formed on said buffer layer through an intermediate semiconductor layer.
Claim 9
Dependent Claim
31 words
A field effect transistor as claimed in Claim 8, wherein: said semi-insulating substrate is composed of GaAs; and said buffer layer being composed of a selected one of GaAs and AlGaAs.
Claim 10
Dependent Claim
17 words
A field effect transistor as claimed in Claim 9, wherein said buffer layer is an undoped layer.
Claim 11
Dependent Claim
18 words
A field effect transistor as claimed in Claim 10, wherein said intermediate semiconductor layer is composed of InAlGaP.
Claim 12
Dependent Claim
29 words
A field effect transistor as claimed in Claim 11, wherein said intermediate semiconductor layer being further composed of an intermediate impurity which is doped in said intermediate semiconductor layer.
Claim 13
Dependent Claim
17 words
A field effect transistor as claimed in Claim 12, wherein said intermediate impurity is an n-type impurity.
Claim 14
Dependent Claim
25 words
A field effect transistor as claimed in Claim 13, wherein said intermediate impurity is one selected from the group consisting of silicon, sulfur, and selenium.
Claim 15
Dependent Claim
28 words
A field effect transistor as claimed in Claim 8, wherein: said semi-insulating substrate is composed of GaAs; and said buffer layer having a superlattice structure composed of AlGaAs/GaAs.
Claim 16
Dependent Claim
17 words
A field effect transistor as claimed in Claim 15, wherein said buffer layer is an undoped layer.
Claim 17
Dependent Claim
18 words
A field effect transistor as claimed in Claim 16, wherein said intermediate semiconductor layer is composed of InAlGaP.
Claim 18
Dependent Claim
29 words
A field effect transistor as claimed in Claim 17, wherein said intermediate semiconductor layer being further composed of an intermediate impurity which is doped in said intermediate semiconductor layer.
Claim 19
Dependent Claim
17 words
A field effect transistor as claimed in Claim 18, wherein said intermediate impurity is an n-type impurity.
Claim 20
Dependent Claim
25 words
A field effect transistor as claimed in Claim 19, wherein said intermediate impurity is one selected from the group consisting of silicon, sulfur, and selenium.
Claim 21
Dependent Claim
34 words
A field effect transistor as claimed in Claim 3, further comprising a semi-insulating substrate and a buffer layer formed on said semi-insulating substrate, wherein said first semiconductor layer is formed on said buffer layer.
Claim 22
Dependent Claim
31 words
A field effect transistor as claimed in Claim 21, wherein: said semi-insulating substrate is composed of GaAs; and said buffer layer being composed of a selected one of GaAs and AlGaAs.
Claim 23
Dependent Claim
17 words
A field effect transistor as claimed in Claim 22, wherein said buffer layer is an undoped layer.
Claim 24
Dependent Claim
61 words
A field effect transistor as claimed in Claim 23, said second semiconductor layer having a layer surface which is divided into a predetermined part and a remaining part, wherein said field effect transistor further comprises: a third semiconductor layer formed on said predetermined part; ohmic electrodes formed on said third semiconductor layer; and a gate electrode formed on said remaining part.
Claim 25
Dependent Claim
25 words
A field effect transistor as claimed in Claim 24, wherein said third semiconductor layer is composed of GaAs and an additional impurity of an n-type.
Claim 26
Dependent Claim
24 words
A field effect transistor as claimed in Claim 25, said additional impurity is one selected from the group consisting of silicon, sulfur, and selenium.
Claim 27
Dependent Claim
17 words
A field effect transistor as claimed in Claim 26, wherein said gate electrode is Schottky gate electrode.
Claim 28
Dependent Claim
28 words
A field effect transistor as claimed in Claim 21, wherein: said semi-insulating substrate is composed of GaAs; and said buffer layer having a superlattice structure composed of AlGaAs/GaAs.
Claim 29
Dependent Claim
17 words
A field effect transistor as claimed in Claim 28, wherein said buffer layer is an undoped layer.
Claim 30
Dependent Claim
61 words
A field effect transistor as claimed in Claim 29, said second semiconductor layer having a layer surface which is divided into a predetermined part and a remaining part, wherein said field effect transistor further comprises: a third semiconductor layer formed on said predetermined part; ohmic electrodes formed on said third semiconductor layer; and a gate electrode formed on said remaining part.
Claim 31
Dependent Claim
25 words
A field effect transistor as claimed in Claim 30, wherein said third semiconductor layer is composed of GaAs and an additional impurity of an n-type.
Claim 32
Dependent Claim
24 words
A field effect transistor as claimed in Claim 31, said additional impurity is one selected from the group consisting of silicon, sulfur, and selenium.
Claim 33
Dependent Claim
17 words
A field effect transistor as claimed in Claim 32, wherein said gate electrode is Schottky gate electrode.
References Cited (Backward Citations)
No citation records indexed.
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