EP0246641A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Heterojunction field-effect device
Assignee: NEC Corp
•
Filing: 1987-05-20
•
Granted: —
•
Expires: 2007-05-20
Abstract
Abstract For high speed operation and improvement in transconductance, there is disclosed a heterojunction field-effect device comprising, a first layer of a first compound semiconductor material having a relatively high donor impurity concentration, a second layer of a second compound semiconductor material formed on the first layer and having a relatively low donor impurity concentration and a relatively large electron affinity, a third layer of high-purity compound semiconductor material formed on the second layer and having a relatively small electron affinity, a gate electrode formed on the third layer, a source electrode formed on one side of the gate electrode and electrically connected to the first and second layers, and a drain electrode formed on the other side of the gate electrode and electrically connected to the first and second layers, so that a carrier-accumulation layer takes place in the second layer of the relatively low donor impurity concentration due to the difference in electron affinity between the second and third layers.
Inventors
- 👤 Hikaru C/O Nec Corporation Hida
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 11:15
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/80; H10D62/82; H10D30/00; H10D30/40; H10D30/47; H10D30/471
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
122 words
A heterojunction field-effect device comprising: 1) a first layer of a first semiconductor material having a relatively high donor impurity concentration; 2) a second layer of a second semiconductor material formed on said first layer and having a relatively low donor impurity concentration and a relatively large electron affinity; 3) a third layer of high-purity semiconductor material formed on said second layer and having a relatively small electron affinity; 4) a gate electrode formed on said third layer; 5) a source electrode formed on one side of said gate electrode and electrically connected to said first and second layers; and 6) a drain electrode formed on the other side of said gate electrode and electrically connected to said first and second layers.
Claim 2
Dependent Claim
54 words
A heterojunction field-effect device as set forth in claim 1, in which said first layer is formed of gallium arsenide having a donor impurity concentration ranging between about 0.5 x 10 18 cm -3 and about 5 x 10 18 cm -3 and a thickness ranging between about 100 angstroms and about 200 angstroms.
Claim 3
Dependent Claim
40 words
A heterojunction field-effect device as set forth in claim 1, in which said second layer is formed of gallium arsenide having a donor impurity concentration lower than 1 x 10 15 cm -3 and a thickness of about 100 angstroms.
Claim 4
Dependent Claim
41 words
A heterojunction field-effect device as set forth in claim 1, in which said third layer is formed of aluminum gallium arsenide having a donor impurity concentration lower than 1 x 10 15 cm -3 and a thickness of about 200 angstroms.
Claim 5
Dependent Claim
22 words
A heterojunction field-effect device as set forth in claim 1, in which said heterojunction field-effect device is fabricated on a semi-insulating structure.
Claim 6
Dependent Claim
47 words
A heterojunction field-effect device as set forth in claim 5, in which said semi-insulating structure comprises a semi-insulating substrate of gallium arsenide and a fourth layer of gallium arsenide having a low impurity atom concentration and having a thickness between about 5000 angstroms and about 1 micron.
Claim 7
Dependent Claim
32 words
A heterojunction field-effect device as set forth in claim 6, in which said fourth layer of gallium arsenide has a donor impurity concentration lower than 1 x 10 15 cm -3 .
Claim 8
Dependent Claim
32 words
A heterojunction field-effect device as set forth in claim 6, in which said fourth layer of gallium arsenide has an acceptor impurity concentration of about 1 x 10 16 cm -3 .
Claim 9
Dependent Claim
35 words
A heterojunction field-effect device as set forth in claim 1, in which said heterojunction field-effect transistor further comprises a multi-layer structure formed between said first layer and said gate electrode and providing a p-n junction.
Claim 10
Dependent Claim
137 words
A heterojunction field-effect device comprising: 1) a first layer of a first semiconductor material having a relatively high acceptor impurity concentration; 2) a second layer of a second semiconductor material formed on said first layer and having a relatively low acceptor impurity concentration and the relatively small sum of the energy band-gap and the electron affinity; 3) a third layer of a high-purity semiconductor material formed on said second layer and having the relatively large sum of the energy band-gap and the electron affinity; 4) a gate electrode formed on said third layer; 5) a source electrode formed on one side of said gate electrode and electrically connected to said first and second layers; and 6) a drain electrode formed on the other side of said gate electrode and electrically connected to said first and second layers.
Claim 11
Dependent Claim
48 words
A heterojunction field-effect device as set forth in claim 10, in which said first layer is formed of germanium having an acceptor impurity concentration ranging between about 0.5 x 10 18 cm -3 and about 5 x 10 18 cm -3 and a thickness of about 100 angstroms.
Claim 12
Dependent Claim
39 words
A heterojunction field-effect device as set forth in claim 10, in which said second layer is formed of germanium having an acceptor impurity concentration lower than 1 x 10 15 cm -3 and a thickness of about 100 angstroms.
Claim 13
Dependent Claim
40 words
A heterojunction field-effect device as set forth in claim 10, in which said third layer is formed of gallium arsenide having an impurity atom concentration lower than 1 x 10 15 cm -3 and a thickness of about 200 angstroms.
Claim 14
Dependent Claim
21 words
A heterojunction field-effect device as set forth in claim 10, in which said field-effect device is fabricated on a semi-insulating structure.
Claim 15
Dependent Claim
42 words
A heterojunction field-effect device as set forth in claim 14, in which said semi-insulating structure comprises a semi-insulating substrate of gallium arsenide and a fourth layer of germanium having an impurity atom concentration lower than 1 x 10 15 cm -3 .
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.