Patent US4583105A successfully refreshed from Google Patents.
US4583105A
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Double heterojunction FET with ohmic semiconductor gate and controllable low threshold voltage
Assignee: International Business Machines Corp
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Filing: 1982-12-30
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Granted: 1986-04-15
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Expires: 2002-12-30
Abstract
Abstract This invention relates to an improved heterojunction FET. More specifically the invention is directed to a heterojunction FET device in which the contact to the semiconductor gate is ohmic in character. The gate and channel regions of the FET have the same barrier height relative to an intervening third layer of semiconductor and sandwich the third layer of undoped semiconductor. The resulting symmetry of the structure provides a threshold voltage which lies normally near zero volts and is controllable upwardly or downwardly by adding an n or p type dopant to the undoped third layer or region.
Inventors
- 👤 James J. Rosenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:09
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/602; H10D30/00; H10D30/40; H10D30/47; H10D30/471; H10D30/475; H10D62/00; H10D62/80; H10D62/82
Claims Analysis
Total Claims: 51
Claim 1
Independent Claim
138 words
A double heterojunction field effect transistor comprising: a first layer of a first single crystal semiconductor material having spaced apart source and drain regions of one conductivity type disposed therein defining a channel region therebetween, a barrier element of a second single crystal semiconductor material different from said first semiconductor material disposed on said first layer over said channel region and forming a heterojunction with said first layer, the band energy difference between said first layer and said barrier element providing a given barrier height and, means having the same potential as said source disposed on said barrier element for controlling at least a band edge of said first layer adjacent said heterojunction so it lies near the fermi level said means relative to said barrier element having a barrier height substantially equal to said given barrier height.
Claim 2
Dependent Claim
138 words
A double heterojunction field effect transistor comprising: a first layer of a first single crystal semiconductor material having spaced apart source and drain regions of one conductivity type disposed therein defining a channel region therebetween, a barrier element of a second single crystal semiconductor material different from said first semiconductor material disposed on said first layer over said channel region and forming a heterojunction with said first layer, the band energy difference between said first layer and said barrier element providing a given barrier height and, means having the same potential as said source disposed on said barrier element for controlling at least a band edge of said first layer adjacent said heterojunction so it lies near the fermi level said means relative to said barrier element having a barrier height substantially equal to said given barrier height.
Claim 3
Dependent Claim
21 words
A double heterojunction field effect transistor according to claim 1 further including an ohmic contact connected to said means for controlling.
Claim 4
Dependent Claim
42 words
A double heterojunction field effect transistor according to claim 1 wherein said means for controlling at least the band edge of said first layer is a layer of single crystal semiconductor material heavily doped with a dopant of said one conductivity type.
Claim 5
Dependent Claim
44 words
A double heterojunction field effect transistor according to claim 1 wherein said means for controlling at least the band edge of said first layer is a layer of said first single crystal semiconductor material heavily doped with a dopant of said one conductivity type.
Claim 6
Dependent Claim
28 words
A double heterojunction field effect transistor according to claim 1 wherein said first semiconductor material is undoped and said regions of one conductivity type are n-conductivity type regions.
Claim 7
Dependent Claim
34 words
A double heterojunction field effect transistor according to claim 1 wherein said first semiconductor material is lightly doped with a p-conductivity type dopant and said regions of one conductivity type are n-conductivity type regions.
Claim 8
Dependent Claim
28 words
A double heterojunction field effect transistor according to claim 1 wherein said first semiconductor material is undoped and said regions of one conductivity type are p-conductivity type regions.
Claim 9
Dependent Claim
27 words
A double heterojunction field effect transistor according to claim 1 wherein at least a portion of said barrier element is made of doped single crystal semiconductor material.
Claim 10
Dependent Claim
29 words
A double heterojunction field effect transistor according to claim 1 wherein at least a portion of said barrier element is doped with a dopant of said one conductivity type.
Claim 11
Dependent Claim
33 words
A double heterojunction field effect transistor according to claim 1 wherein at least a portion of said barrier element is doped with a dopant of opposite conductivity type to said one conductivity type.
Claim 12
Dependent Claim
62 words
A double heterojunction field effect transistor according to claim 1 wherein said first single crystal semiconductor material is gallium arsenide and said spaced apart source and drain regions are of n-conductivity type, said second semiconductor material different from said first semiconductor material is gallium aluminum arsenide and said means for controlling is a gate layer of gallium arsenide heavily doped with silicon.
Claim 13
Dependent Claim
62 words
A double heterojunction field effect transistor according to claim 1 wherein said first single crystal semiconductor material is germanium and said spaced apart source and drain regions are of p-conductivity type doped with gallium, said second semiconductor material different from said first semiconductor material is zinc selenide and said means for controlling is a gate layer of germanium heavily doped with gallium.
Claim 14
Dependent Claim
67 words
A double heterojunction field effect transistor according to claim 1 wherein said first single crystal semiconductor material is germanium and said spaced apart source and drain regions are of n-conductivity type doped with arsenic or antimony, said second semiconductor material different from said first semiconductor material is gallium aluminum arsenide and said means for controlling is a gate layer of germanium heavily doped with arsenic or antimony.
Claim 15
Dependent Claim
63 words
A double heterojunction field effect transistor according to claim 1 wherein said first single crystal semiconductor material is germanium and said spaced apart source and drain regions are of p-conductivity type doped with gallium, said second semiconductor material different from said first semiconductor material is gallium aluminum arsenide and said means for controlling is a gate layer of germanium heavily doped with gallium.
Claim 16
Dependent Claim
68 words
A double heterojunction field effect transistor according to claim 1 wherein said first single crystal semiconductor material is indium arsenide and said spaced apart source and drain regions are of n-conductivity type doped with selenium or tellurium, said second semiconductor material different from said first semiconductor material is zinc telluride and said means for controlling is a gate layer of indium arsenide heavily doped with selenium or tellurium.
Claim 17
Dependent Claim
17 words
A double heterojunction field effect transistor according to claim 11 further including an ohmic contact of gold-germanium.
Claim 18
Dependent Claim
19 words
A double heterojunction field effect transistor according to claim 12 further including an ohmic contact of indium or tin.
Claim 19
Dependent Claim
19 words
A double heterojunction field effect transistor according to claim 13 further including an ohmic contact of indium or tin.
Claim 20
Dependent Claim
19 words
A double heterojunction field effect transistor according to claim 14 further including an ohmic contact of indium or tin.
Claim 21
Dependent Claim
17 words
A double heterojunction field effect transistor according to claim 15 further including an ohmic contact of gold.
Claim 22
Dependent Claim
136 words
A double heterojunction field effect transistor comprising: a first layer of single crystal semiconductor material having spaced apart source and drain regions of one conductivity type disposed therein defining a channel region therebetween, a barrier element of a second crystal semiconductor material different from said first semiconductor material disposed on said first layer over said channel region and forming a heterojunction with said first layer, the band energy difference between said first layer and said barrier element providing a given barrier height, and, means having the same potential as said source disposed on said barrier element for controlling at least the conduction band edge of said first layer adjacent said heterojunction so it lies near the fermi level, said means relative to said barrier element having a barrier height substantially equal to said given barrier height.
Claim 23
Dependent Claim
136 words
A double heterojunction field effect transistor comprising: a first layer of single crystal semiconductor material having spaced apart source and drain regions of one conductivity type disposed therein defining a channel region therebetween, a barrier element of a second crystal semiconductor material different from said first semiconductor material disposed on said first layer over said channel region and forming a heterojunction with said first layer, the band energy difference between said first layer and said barrier element providing a given barrier height, and, means having the same potential as said source disposed on said barrier element for controlling at least the conduction band edge of said first layer adjacent said heterojunction so it lies near the fermi level, said means relative to said barrier element having a barrier height substantially equal to said given barrier height.
Claim 24
Dependent Claim
21 words
A double heterojunction field effect transistor according to claim 21 further including an ohmic contact connected to said means for controlling.
Claim 25
Dependent Claim
43 words
A double heterojunction field effect trasistor according to claim 21 wherein said means for controlling at least the conduction band edge of said first layer is a layer of single crystal semiconductor material heavily doped with a dopant of said one conductivity type.
Claim 26
Dependent Claim
45 words
A double heterojunction field effect transistor according to claim 21 wherein said means for controlling at least the conduction band edge of said first layer is a layer of said first single crystal semiconductor material heavily doped with a dopant of said one conductivity type.
Claim 27
Dependent Claim
27 words
A double heterojunction field effect transistor according to claim 21 wherein said first semiconductor material is undoped and said regions of one conductivity type are n-conductivity type.
Claim 28
Dependent Claim
34 words
A double heterojunction field effect transistor according to claim 21 wherein said first semiconductor material is lightly doped with a p-conductivity type dopant and said regions of one conductivity type are n-conductivity type regions.
Claim 29
Dependent Claim
27 words
A double heterojunction field effect transistor according to claim 21 wherein at least a portion of said barrier element is made of doped single crystal semiconductor material.
Claim 30
Dependent Claim
29 words
A double heterojunction field effect transistor according to claim 21 wherein at least a portion of said barrier element is doped with a dopant of said one conductivity type.
Claim 31
Dependent Claim
33 words
A double heterojunction field effect transistor according to claim 21 wherein at least a portion of said barrier element is doped with a dopant of opposite conductivity type to said one conductivity type.
Claim 32
Dependent Claim
62 words
A double heterojunction field effect transistor according to claim 21 wherein said first single crystal semiconductor material is gallium arsenide and said spaced apart source and drain regions are of n-conductivity type, said second semiconductor material different from said first semiconductor material is gallium aluminum arsenide and said means for controlling is a gate layer of gallium arsenide heavily doped with silicon
Claim 33
Dependent Claim
68 words
A double heterojunction field effect transistor according to claim 21 wherein said first single crystal semiconductor material is indium arsenide and said spaced apart source and drain regions are of n-conductivity type doped with selenium or tellurium, said second semiconductor material different from said first semiconductor material is zinc telluride and said means for controlling is a gate layer of indium arsenide heavily doped with selenium or tellurium.
Claim 34
Dependent Claim
67 words
A double heterojunction field effect transistor according to claim 21 wherein said first single crystal semiconductor material is germanium and said spaced apart source and drain regions are of n-conductivity type doped with arsenic or antimony, said second semiconductor material different from said first semiconductor material is gallium aluminum arsenide and said means for controlling is a gate layer of germanium heavily doped with arsenic or antimony.
Claim 35
Dependent Claim
17 words
A double heterojunction field effect transistor according to claim 30 further including an ohmic contact of gold-germanium.
Claim 36
Dependent Claim
17 words
A double heterojunction field effect transistor according to claim 31 further including an ohmic contact of gold.
Claim 37
Dependent Claim
19 words
A double heterojunction field effect transistor according to claim 32 further including an ohmic contact of indium or tin.
Claim 38
Dependent Claim
137 words
A double heterojunction field effect transistor comprising: a first layer of a first single crystal semiconductor material having spaced apart source and drain regions of one conductivity type disposed therein defining a channel region therebetween, a barrier element of a second crystal semiconductor material different from said first semiconductor material disposed on said first layer over channel region and forming a heterojunction with said first layer, the band energy difference between said first layer and said barrier element providing a given barrier height, and means having the same potential as said source disposed on said barrier element for controlling at least the valence band edge of said first layer adjacent said heterojunction so it lies near the fermi level said means relative to said barrier element having a barrier height substantially equal to said given barrier height.
Claim 39
Dependent Claim
137 words
A double heterojunction field effect transistor comprising: a first layer of a first single crystal semiconductor material having spaced apart source and drain regions of one conductivity type disposed therein defining a channel region therebetween, a barrier element of a second crystal semiconductor material different from said first semiconductor material disposed on said first layer over channel region and forming a heterojunction with said first layer, the band energy difference between said first layer and said barrier element providing a given barrier height, and means having the same potential as said source disposed on said barrier element for controlling at least the valence band edge of said first layer adjacent said heterojunction so it lies near the fermi level said means relative to said barrier element having a barrier height substantially equal to said given barrier height.
Claim 40
Dependent Claim
21 words
A double heterojunction field effect transistor according to claim 36 further including an ohmic contact connected to said means for controlling.
Claim 41
Dependent Claim
43 words
A double heterojunction field effect transistor according to claim 36 wherein said means for controlling at least the valence band edge of said first layer is a layer of single crystal semiconductor material heavily doped with a dopant of said one conductivity type.
Claim 42
Dependent Claim
45 words
A double heterojunction field effect transistor according to claim 36 wherein said means for controlling at least the valence band edge of said first layer is a layer of said first single crystal semiconductor material heavily doped with a dopant of said one conductivity type.
Claim 43
Dependent Claim
27 words
A double heterojunction field effect transistor according to claim 36 wherein said first semiconductor material is undoped and said regions of one conductivity type are p-conductivity type.
Claim 44
Dependent Claim
34 words
A double heterojunction field effect transistor according to claim 36 wherein said first semiconductor material is lightly doped with an n-conductivity type dopant and said regions of one conductivity type are p-conductivity type regions.
Claim 45
Dependent Claim
27 words
A double heterojunction field effect transistor according to claim 36 wherein at least a portion of said barrier element is made of doped single crystal semiconductor material.
Claim 46
Dependent Claim
29 words
A double heterojunction field effect transistor according to claim 36 wherein at least a portion of said barrier element is doped with a dopant of said one conductivity type.
Claim 47
Dependent Claim
33 words
A double heterojunction field effect transistor according to claim 36 wherein at least a portion of said barrier element is doped with a dopant of opposite conductivity type to said one conductivity type.
Claim 48
Dependent Claim
61 words
A double heterojunction field effect transistor according to claim 36 wherein said first single crystal semiconductor material is germanium and said spaced-apart source and drain regions are of p-conductivity type doped with gallium, said second semiconductor material different from said first semiconductor material is zinc selenide and said means for controlling is a gate layer of germanium heavily doped with gallium.
Claim 49
Dependent Claim
62 words
A double heterojunction field effect transistor according to claim 36 wherein said first single crystal semiconductor material is germanium and said spaced-apart source and drain regions are of p-conductivity type doped with gallium, said second semiconductor material different from said first semiconductor material is gallium aluminum arsenide and said means for controlling is a gate layer of germanium heavily doped with gallium.
Claim 50
Dependent Claim
18 words
A double heterojunction field effect transistor according to claim 45 further including an ohmic of indium or tin.
Claim 51
Dependent Claim
19 words
A double heterojunction field effect transistor according to claim 46 further including an ohmic contact of indium or tin.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |