Patent US5907164A successfully refreshed from Google Patents.
US5907164A
Expired / Lapsed
US
⏱️ 0.0 years remaining
InAlAs/InGaAs heterojunction field effect type semiconductor device
Assignee: NEC Corp
•
Filing: 1996-12-16
•
Granted: 1999-05-25
•
Expires: 2016-12-16
Abstract
Abstract In an InAlAs/InGaAs heterojunction field type semiconductor device including an InP substrate, a superlattice layer formed by periods of InAs/AlAs or InAs/AlGaAs is formed over an InGaAs channel layer which is formed over the InP substrate.
Inventors
- 👤 Tatsuo Nakayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:48
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/80; H10D62/81; H10D62/815; H10D62/8161; H10D62/8162; H10D62/8164; H10D30/00; H10D30/40; H10D30/47; H10D30/471; H10D30/473; H10D30/4732
Claims Analysis
Total Claims: 46
Claim 1
Independent Claim
53 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an InGaAs channel layer formed over said InP substrate; a superlattice layer formed by periods of InAs/AlAs and over said InGaAs channel layer; a first InAlAs layer formed beneath said superlattice layer; and a second InAlAs layer formed on said superlattice layer.
Claim 2
Dependent Claim
53 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an InGaAs channel layer formed over said InP substrate; a superlattice layer formed by periods of InAs/AlAs and over said InGaAs channel layer; a first InAlAs layer formed beneath said superlattice layer; and a second InAlAs layer formed on said superlattice layer.
Claim 3
Dependent Claim
25 words
The device as set forth in claim 1, further comprising an InAlAs charge supply layer formed between said InGaAs channel layer and said superlattice layer.
Claim 4
Dependent Claim
18 words
The device as set forth in claim 2, wherein said superlattice layer is thinner than approximately 25 nm.
Claim 5
Dependent Claim
31 words
The device as set forth in claim 1, wherein the ratio of average lattice constant of said superlattice layer to lattice constant of said InP substrate is approximately 0.995 to 1.005.
Claim 6
Dependent Claim
26 words
The device as set forth in claim 1, wherein each of said InAs and said AlAs of said superlattice layer is thinner than approximately 4 nm.
Claim 7
Dependent Claim
27 words
The device as set forth in claim 1, wherein the thickness ratio of said InAs and said AlAs of said superlattice layer is approximately 0.5 to 2.
Claim 8
Dependent Claim
54 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an InGaAs channel layer formed over said InP substrate; and a superlattice layer formed by periods of InAs/AlGaAs and over said InGaAs channel layer; a first InAlAs layer formed beneath said superlattice layer; and a second InAlAs layer formed on said superlattice layer.
Claim 9
Dependent Claim
54 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an InGaAs channel layer formed over said InP substrate; and a superlattice layer formed by periods of InAs/AlGaAs and over said InGaAs channel layer; a first InAlAs layer formed beneath said superlattice layer; and a second InAlAs layer formed on said superlattice layer.
Claim 10
Dependent Claim
25 words
The device as set forth in claim 7, further comprising an InAlAs charge supply layer formed between said InGaAs channel layer and said superlattice layer.
Claim 11
Dependent Claim
18 words
The device as set forth in claim 8, wherein said superlattice layer is thinner than approximately 25 nm.
Claim 12
Dependent Claim
31 words
The device as set forth in claim 7, wherein the ratio of average lattice constant of said superlattice layer to lattice constant of said InP substrate is approximately 0.995 to 1.005.
Claim 13
Dependent Claim
26 words
The device as set forth in claim 7, wherein each of said InAs and said AlGaAs of said superlattice layer is thinner than approximately 4 nm.
Claim 14
Dependent Claim
26 words
The device as set forth in claim 7, wherein thickness ratio of said InAs and said AlGaAs of said superlattice layer is approximately 0.5 to 2.
Claim 15
Dependent Claim
107 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the ratio of average lattice constant of said superlattice layer to lattice constant of said InP substrate is approximately 0.995 to 1.005.
Claim 16
Dependent Claim
107 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the ratio of average lattice constant of said superlattice layer to lattice constant of said InP substrate is approximately 0.995 to 1.005.
Claim 17
Dependent Claim
107 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the ratio of average lattice constant of said superlattice layer to lattice constant of said InP substrate is approximately 0.995 to 1.005.
Claim 18
Dependent Claim
107 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the ratio of average lattice constant of said superlattice layer to lattice constant of said InP substrate is approximately 0.995 to 1.005.
Claim 19
Dependent Claim
107 words
A heterojunction field effect type semiconductor device comprising: an InP substrate an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the ratio of average lattice constant of said superlattice layer to lattice constant of said InP substrate is approximately 0.995 to 1.005.
Claim 20
Dependent Claim
107 words
A heterojunction field effect type semiconductor device comprising: an InP substrate an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the ratio of average lattice constant of said superlattice layer to lattice constant of said InP substrate is approximately 0.995 to 1.005.
Claim 21
Dependent Claim
107 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the ratio of average lattice constant of said superlattice layer to lattice constant of said InP substrate is approximately 0.995 to 1.005.
Claim 22
Dependent Claim
107 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the ratio of average lattice constant of said superlattice layer to lattice constant of said InP substrate is approximately 0.995 to 1.005.
Claim 23
Dependent Claim
108 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a first InAlAs Schottky layer formed on said InAlAs carrier supply layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one four-molecules-thick AlAs layer on said first InAlAs Schottky layer; s second InAlAs Schottky layer formed on said supperlattice layer; and electrodes formed on said second InAlAs Schottky layer.
Claim 24
Dependent Claim
108 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a first InAlAs Schottky layer formed on said InAlAs carrier supply layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one four-molecules-thick AlAs layer on said first InAlAs Schottky layer; s second InAlAs Schottky layer formed on said supperlattice layer; and electrodes formed on said second InAlAs Schottky layer.
Claim 25
Dependent Claim
108 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a first InAlAs Schottky layer formed on said InAlAs carrier supply layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlAs layer on said first InAlAs Schottky layer; s second InAlAs Schottky layer formed on said supperlattice layer; and electrodes formed on said second InAlAs Schottky layer.
Claim 26
Dependent Claim
108 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a first InAlAs Schottky layer formed on said InAlAs carrier supply layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlAs layer on said first InAlAs Schottky layer; s second InAlAs Schottky layer formed on said supperlattice layer; and electrodes formed on said second InAlAs Schottky layer.
Claim 27
Dependent Claim
108 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a first InAlAs Schottky layer formed on said InAlAs carrier supply layer; a superlattice layer formed by periods of one two-molecules-thick InGaAs layer and one four-molecules-thick AlAs layer on said first InAlAs Schottky layer; s second InAlAs Schottky layer formed on said supperlattice layer; and electrodes formed on said second InAlAs Schottky layer.
Claim 28
Dependent Claim
108 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a first InAlAs Schottky layer formed on said InAlAs carrier supply layer; a superlattice layer formed by periods of one two-molecules-thick InGaAs layer and one four-molecules-thick AlAs layer on said first InAlAs Schottky layer; s second InAlAs Schottky layer formed on said supperlattice layer; and electrodes formed on said second InAlAs Schottky layer.
Claim 29
Dependent Claim
108 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a first InAlAs Schottky layer formed on said InAlAs carrier supply layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlGaAs layer on said first InAlAs Schottky layer; s second InAlAs Schottky layer formed on said supperlattice layer; and electrodes formed on said second InAlAs Schottky layer.
Claim 30
Dependent Claim
108 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a first InAlAs Schottky layer formed on said InAlAs carrier supply layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlGaAs layer on said first InAlAs Schottky layer; s second InAlAs Schottky layer formed on said supperlattice layer; and electrodes formed on said second InAlAs Schottky layer.
Claim 31
Dependent Claim
103 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein each of said InAs and said AlAs layers of said superlattice layer is thinner than approximately 4 nm.
Claim 32
Dependent Claim
103 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein each of said InAs and said AlAs layers of said superlattice layer is thinner than approximately 4 nm.
Claim 33
Dependent Claim
103 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein each of said InAs and said AlAs layers of said superlattice layer is thinner than approximately 4 nm.
Claim 34
Dependent Claim
103 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein each of said InAs and said AlAs layers of said superlattice layer is thinner than approximately 4 nm.
Claim 35
Dependent Claim
103 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein each of said InAs and said AlGaAs layers of said superlattice layer is thinner than approximately 4 nm.
Claim 36
Dependent Claim
103 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein each of said InAs and said AlGaAs layers of said superlattice layer is thinner than approximately 4 nm.
Claim 37
Dependent Claim
103 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein each of said InAs and said AlGaAs layers of said superlattice layer is thinner than approximately 4 nm.
Claim 38
Dependent Claim
103 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein each of said InAs and said AlGaAs layers of said superlattice layer is thinner than approximately 4 nm.
Claim 39
Dependent Claim
114 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the thickness ratio of said InAs and said AlAs layers of said superlattice layer is approximately 0.5 to 2, and said superlattice layer is thinner than approximately 25 nm.
Claim 40
Dependent Claim
114 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the thickness ratio of said InAs and said AlAs layers of said superlattice layer is approximately 0.5 to 2, and said superlattice layer is thinner than approximately 25 nm.
Claim 41
Dependent Claim
113 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules thick AlAs layer on said InAlAs carrier supply; and electrodes formed on said superlattice layer; wherein the thickness ratio of said InAs and said AlAs layers of said superlattice layer is approximately 0.5 to 2, and said superlattice layer is thinner than approximately 25 nm.
Claim 42
Dependent Claim
113 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules thick AlAs layer on said InAlAs carrier supply; and electrodes formed on said superlattice layer; wherein the thickness ratio of said InAs and said AlAs layers of said superlattice layer is approximately 0.5 to 2, and said superlattice layer is thinner than approximately 25 nm.
Claim 43
Dependent Claim
114 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the thickness ratio of said InAs and said AlGaAs layers of said superlattice layer is approximately 0.5 to 2, and said superlattice layer is thinner than approximately 25 nm.
Claim 44
Dependent Claim
114 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one three-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the thickness ratio of said InAs and said AlGaAs layers of said superlattice layer is approximately 0.5 to 2, and said superlattice layer is thinner than approximately 25 nm.
Claim 45
Dependent Claim
114 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the superlattice ratio of said InAs and said AlGaAs layers of said superlattice layer is approximately 0.5 to 2, and said superlattice layer is thinner than approximately 25 nm.
Claim 46
Dependent Claim
114 words
A heterojunction field effect type semiconductor device comprising: an InP substrate; an undoped InAlAs buffer layer formed on said InP substrate; an undoped InGaAs channel layer formed on said InAlAs buffer layer; an undoped InAlAs spacer layer formed on said InGaAs channel layer; a doped InAlAs carrier supply layer formed on said InAlAs spacer layer; a superlattice layer formed by periods of one two-molecules-thick InAs layer and one two-molecules-thick AlGaAs layer on said InAlAs carrier supply layer; and electrodes formed on said superlattice layer; wherein the superlattice ratio of said InAs and said AlGaAs layers of said superlattice layer is approximately 0.5 to 2, and said superlattice layer is thinner than approximately 25 nm.
References Cited (Backward Citations)
JPS63311772A
Cited
JPH0485939A
Cited
US5206528A
Cited
US5420442A
Cited
EP0569259A2
Cited
US5268582A
Cited
JPH07142513A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-05-24 | 2002-11-23 | 2003-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-24 | 2006-11-23 | 2007-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-24 | 2010-11-23 | 2011-05-25 | $7700.00 | Window Closed / Lapsed |