US5024958A
Expired / Lapsed
US
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Compound semiconductor device and a manufacturing method thereof
Assignee: Fujitsu Ltd
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Filing: 1990-10-25
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Granted: 1991-06-18
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Expires: 2010-10-25
Abstract
Abstract A high-speed compound semiconductor device includes semiconductor layers of a group III-V alloy laminated in a vertical direction. The device uses a base electrode that contacts side walls and covers a step portion of a base layer. The device includes an intermediate layer positioned between and comprising a different semiconductor material than that of base and collector layers. The intermediate layer has a different etching rate than those of the base and collector layers. The intermediate layer can be a collector-side barrier layer formed between the collector and base layers in a HET or RHET device. The device of the present invention has reduced capacitance between the base and collector layers and reduced base layer resistance.
Inventors
- 👤 Yuji Awano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:46
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/20; H10D64/27; H10D64/281; H10D10/00; H10D10/80; H10D10/821; H10D10/881; H10D48/00; H10D48/30; H10D48/32; H10D48/36; H10D48/362
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
144 words
A method of manufacturing a compound semiconductor device including a substrate, comprising the steps of: (a) forming a first layer of at least a first compound semiconductor on the substrate so as to form a mesa of the first layer, the mesa having a top area including a contact area; (b) forming an intermediate layer of a second compound semiconductor on said contact area of said first layer: (c) forming a second layer of at least said first compound semiconductor on a region of said intermediate layer overlying at least said contact area so as to form side walls and a top portion of said second layer; (d) forming an electrode so as to contact said side walls and a part of said top portion of said second layer; and (e) forming a third layer of said first compound semiconductor overlying said second layer.
Claim 2
Independent Claim
144 words
A method of manufacturing a compound semiconductor device including a substrate, comprising the steps of: (a) forming a first layer of at least a first compound semiconductor on the substrate so as to form a mesa of the first layer, the mesa having a top area including a contact area; (b) forming an intermediate layer of a second compound semiconductor on said contact area of said first layer: (c) forming a second layer of at least said first compound semiconductor on a region of said intermediate layer overlying at least said contact area so as to form side walls and a top portion of said second layer; (d) forming an electrode so as to contact said side walls and a part of said top portion of said second layer; and (e) forming a third layer of said first compound semiconductor overlying said second layer.
Claim 3
Dependent Claim
40 words
A method of manufacturing a compound semiconductor device according to claim 1, wherein step (a) includes the substep of: (1) forming said mesa of said first layer such that said mesa has a top area corresponding to said contact area.
Claim 4
Dependent Claim
39 words
A method of manufacturing a compound semiconductor device according to claim 2, Wherein step (a) further includes the substep of: (2) isotropically removing said first layer so as to form eaves of said intermediate layer extending from said mesa.
Claim 5
Dependent Claim
37 words
A method of manufacturing a compound semiconductor device according to claim 1, further including the step of: (f) anisotropically removing a portion of said third layer so as to expose said top portion of said second layer.
Claim 6
Dependent Claim
31 words
A method of manufacturing a compound semiconductor device according to claim 2, wherein step (c) includes the substep of: (1) forming a mesa of said second layer overlying said contact area.
Claim 7
Independent Claim
168 words
A method of manufacturing a compound semiconductor device including a substrate, comprising the steps of: (a) forming a first layer including at least a first compound semiconductor on the substrate; (b) forming an intermediate layer of a second compound semiconductor on the first layer; (c) forming a second layer of at least the first compound semiconductor on the intermediate layer; (d) forming a third layer of the first compound semiconductor overlying the second layer; (e) forming a mesa portion of the second and third layers so as to form side walls and a step portion of the second layer, the mesa portion having a first contact area with the intermediate layer; (f) forming a mesa portion of a first layer underlying the intermediate layer, the mesa portion of the first layer having a second contact area with the intermediate layer that is not larger than the first contact area; and (g) forming an electrode contacting the side walls and covering at least a part of the step portion.
Claim 8
Independent Claim
168 words
A method of manufacturing a compound semiconductor device including a substrate, comprising the steps of: (a) forming a first layer including at least a first compound semiconductor on the substrate; (b) forming an intermediate layer of a second compound semiconductor on the first layer; (c) forming a second layer of at least the first compound semiconductor on the intermediate layer; (d) forming a third layer of the first compound semiconductor overlying the second layer; (e) forming a mesa portion of the second and third layers so as to form side walls and a step portion of the second layer, the mesa portion having a first contact area with the intermediate layer; (f) forming a mesa portion of a first layer underlying the intermediate layer, the mesa portion of the first layer having a second contact area with the intermediate layer that is not larger than the first contact area; and (g) forming an electrode contacting the side walls and covering at least a part of the step portion.
Claim 9
Dependent Claim
27 words
A method of manufacturing a compound semiconductor device according to claim 6, wherein step (g) includes the substep of: (1) isolating the electrode from the third layer.
Claim 10
Dependent Claim
33 words
A method of manufacturing a compound semiconductor device according to claim 7, wherein step (f) includes the substep of: (1) removing a portion of the intermediate layer outside of the first contact area.
Claim 11
Dependent Claim
34 words
A method of manufacturing a compound semiconductor device according to claim 7, wherein step (g) further includes the substep of: (2) forming the electrode on the intermediate layer outside of the first contact area.
Claim 12
Dependent Claim
39 words
A method of manufacturing a compound semiconductor device according to claim 6, wherein step (e) includes the substep of: (1) forming the mesa portion of the second and third layers by anisotropically removing a portion of the third layer.
Claim 13
Dependent Claim
39 words
A method of manufacturing a compound semiconductor device according to claim 10, wherein step (f) includes the substep of: (1) isotropically removing a portion of the first layer so as to form the mesa portion of the first layer.
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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) | 1994-06-17 | 1994-12-17 | 1995-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-17 | 1998-12-17 | 1999-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-17 | 2002-12-17 | 2003-06-18 | $7700.00 | Window Closed / Lapsed |