Patent US5109256A successfully refreshed from Google Patents.
US5109256A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Schottky barrier diodes and Schottky barrier diode-clamped transistors and method of fabrication
Assignee: National Semiconductor Corp
•
Filing: 1990-08-17
•
Granted: 1992-04-28
•
Expires: 2010-08-17
Abstract
Abstract A Schottky diode is formed with a layer of intrinsic polysilicon separating a metal silicide layer from an n conductivity type active region. This structure avoids the necessity for a process step which opens a window in the intrinsic polysilicon layer and reduces the portion of surface area needed for formation of a Schottky diode, compared to previous devices. The Schottky diode can be formed as part of an overall process for forming an integrated circuit and can be positioned in parallel across the collector/base junction of a bipolar transistor to form a Schottky barrier diode-clamped transistor.
Inventors
- 👤 Bancherd De Long
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:28
CPC Classifications
H; H10; H10D; H10D64/00; H10D8/00; H10D8/60; H10D84/00; H10D84/101; H10D84/121
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
127 words
A Schottky barrier diode comprising: a layer of n-doped silicon having an upper surface, said n-doped silicon forming the cathode of said Schottky barrier diode; a layer of intrinsic polysilicon adjacent said upper surface of said layer of n-doped silicon, said layer of intrinsic polysilicon having an upper surface; a layer of metal silicide having a first portion adjacent said upper surface of said layer of intrinsic polysilicon said first portion of said metal silicide-forming the anode of said Schottky barrier diode; first cathode contact means positioned at a level above said upper surface of said layer of N-doped silicon and spaced from said anode; and a low resistance connection region for providing electrical connection between said layer of n-doped silicon and said first cathode contact means.
Claim 2
Dependent Claim
127 words
A Schottky barrier diode comprising: a layer of n-doped silicon having an upper surface, said n-doped silicon forming the cathode of said Schottky barrier diode; a layer of intrinsic polysilicon adjacent said upper surface of said layer of n-doped silicon, said layer of intrinsic polysilicon having an upper surface; a layer of metal silicide having a first portion adjacent said upper surface of said layer of intrinsic polysilicon said first portion of said metal silicide-forming the anode of said Schottky barrier diode; first cathode contact means positioned at a level above said upper surface of said layer of N-doped silicon and spaced from said anode; and a low resistance connection region for providing electrical connection between said layer of n-doped silicon and said first cathode contact means.
Claim 3
Dependent Claim
23 words
A Schottky barrier diode, as claimed in claim 1, wherein said connection region comprises an n-type active layer formed in an integrated circuit.
Claim 4
Dependent Claim
25 words
A Schottky barrier diode, as claimed in claim 1, further comprising a second contact means for providing electrical connection to said layer of metal silicide.
Claim 5
Dependent Claim
30 words
A Schottky barrier diode, as claimed in claim 3, wherein said second contact means comprises a layer of metal adjacent at least a part of said layer of metal silicide.
Claim 6
Dependent Claim
46 words
A Schottky barrier diode, as claimed in claim 1, wherein said Schottky barrier diode is formed as part of an integrated circuit, said integrated circuit including a bipolar transistor; and wherein said low resistance connection region provides electrical connection tot eh collector of said bipolar transistor.
Claim 7
Dependent Claim
120 words
A Schottky barrier diode, formed as part of an integrated circuit, said integrated circuit including a bipolar transistor, the Schottky barrier diode comprising: a layer of n-doped silicon having an upper surface, said n-doped silicon forming the cathode of said Schottky barrier diode; a layer of intrinsic polysilicon adjacent said upper surface of said layer of n-doped silicon, said layer of intrinsic polysilicon having an upper surface; a layer of metal silicide having a first portion adjacent said upper surface of said layer of intrinsic polysilicon said first portion of said metal silicide-forming the anode of said Schottky barrier diode; wherein said metal silicide layer is in contact with at least a portion of the base of said bipolar transistor.
Claim 8
Dependent Claim
120 words
A Schottky barrier diode, formed as part of an integrated circuit, said integrated circuit including a bipolar transistor, the Schottky barrier diode comprising: a layer of n-doped silicon having an upper surface, said n-doped silicon forming the cathode of said Schottky barrier diode; a layer of intrinsic polysilicon adjacent said upper surface of said layer of n-doped silicon, said layer of intrinsic polysilicon having an upper surface; a layer of metal silicide having a first portion adjacent said upper surface of said layer of intrinsic polysilicon said first portion of said metal silicide-forming the anode of said Schottky barrier diode; wherein said metal silicide layer is in contact with at least a portion of the base of said bipolar transistor.
Claim 9
Dependent Claim
76 words
A Schottky barrier diode-clamped transistor comprising: a substrate containing active regions forming collector, emitter and base regions of a bipolar transistor; doped polysilicon regions adjacent said substrate forming collector, emitter and base contacts; at least a first intrinsic polysilicon region adjacent a portion of said collector region; metal silicide overlying at least said intrinsic polysilicon and said base contact, wherein at least a portion of said metal silicide forms the anode of a Schottky barrier diode.
Claim 10
Dependent Claim
76 words
A Schottky barrier diode-clamped transistor comprising: a substrate containing active regions forming collector, emitter and base regions of a bipolar transistor; doped polysilicon regions adjacent said substrate forming collector, emitter and base contacts; at least a first intrinsic polysilicon region adjacent a portion of said collector region; metal silicide overlying at least said intrinsic polysilicon and said base contact, wherein at least a portion of said metal silicide forms the anode of a Schottky barrier diode.
Claim 11
Dependent Claim
26 words
A Schottky barrier diode-clamped transistor, as claimed in claim 7, wherein said Schottky barrier diode is connected in parallel with the collector-base junction of said transistor.
References Cited (Backward Citations)
US3790817A
Cited
US3955269A
Cited
US4220961A
Cited
US4628339A
Cited
US4543595A
Cited
US4507847A
Cited
US4484388A
Cited
US4536945A
Cited
US4609568A
Cited
US4764480A
Cited
US4732873A
Cited
US4795722A
Cited
US4829025A
Cited
US4897364A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-04-28 | 1995-10-28 | 1996-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-28 | 1999-10-28 | 2000-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-28 | 2003-10-28 | 2004-04-28 | $7700.00 | Window Closed / Lapsed |