Patent US4757025A successfully refreshed from Google Patents.
US4757025A
Expired / Lapsed
US
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Method of making gate turn off switch with anode short and buried base
Assignee: Semiconductor Components Industries LLC
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Filing: 1986-11-28
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Granted: 1988-07-12
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Expires: 2006-11-28
Abstract
Abstract A GTO switch is provided in which the upper base layer (gate) is formed by a diffusion step. An epitaxial layer grown over the upper base layer contains cathode and gate diffusions which are separated by an undiffused gap. This "buried base" technique provides precise control over the resistivity of the base. The cathode-gate gap provides increased reverse gate voltage capacity. Other features include a large anode short area and a double-layer-metal; contact structure on the cathode-gate surface.
Inventors
- 👤 John R. Bender
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:43
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H10D62/141; H10D62/148; H10D18/00; H10D18/60; H10D62/17; H10D62/192; H10D62/206
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
189 words
A method of manufacturing a gate-controlled switch comprising the steps of: providing a body of semiconductor material of a second conductivity type, said body having a first major surface and a second major surface opposite said first major surface; forming a base layer of semiconductor material of a first conductivity type at said first major surface of said body; growing a layer of epitaxial semiconductor material of said second conductivity type overlaying said first major surface of said body; forming a gate region of said first conductivity type in said layer of epitaxial material, said gate region being contiguous with said base layer; forming an anode region of said first conductivity type in said body, said anode region being contiguous with said second major surface of said body; forming a cathode region of said second conductivity type in said layer of epitaxial material, said cathode region being separated from said gate region; and forming an anode shorting region of said second conductivity type in said body, said anode shorting region being contiguous with said second major surface of said body and disposed about a portion of said anode region.
Claim 2
Independent Claim
189 words
A method of manufacturing a gate-controlled switch comprising the steps of: providing a body of semiconductor material of a second conductivity type, said body having a first major surface and a second major surface opposite said first major surface; forming a base layer of semiconductor material of a first conductivity type at said first major surface of said body; growing a layer of epitaxial semiconductor material of said second conductivity type overlaying said first major surface of said body; forming a gate region of said first conductivity type in said layer of epitaxial material, said gate region being contiguous with said base layer; forming an anode region of said first conductivity type in said body, said anode region being contiguous with said second major surface of said body; forming a cathode region of said second conductivity type in said layer of epitaxial material, said cathode region being separated from said gate region; and forming an anode shorting region of said second conductivity type in said body, said anode shorting region being contiguous with said second major surface of said body and disposed about a portion of said anode region.
Claim 3
Dependent Claim
50 words
A method according to claim 1 wherein said step of growing a layer of epitaxial semiconductor material further comprises the step of: introducing a dopant of said second conductivity type in a concentration sufficient to produce a resistivity in the range of 50 to 200 ohm centimeters in said layer.
Claim 4
Dependent Claim
24 words
A method according to claim 1 wherein: said base layer has a sheet resistivity in the range of 40 to 100 ohms per square.
Claim 5
Dependent Claim
15 words
The method of claim 1 wherein said anode region is juxtaposed to said cathode region.
Claim 6
Independent Claim
212 words
A method of manufacturing a gate-controlled switch comprising the steps of: providing a body of semiconductor material of a second conductivity type, said body having a first major surface and a second major surface opposite said first major surface; forming a base layer of semiconductor material of a first conductivity type at said first major surface of said body; growing a layer of epitaxial semiconductor material of said second conductivity type overlaying said first major surface of said body; forming a first and second gate regions of said first conductivity type in said layer of epitaxial material, said first and second gate regions being contiguous with said base layer; forming an anode region of said first conductivity type in said body, said anode region being contiguous with said second major surface of said body; forming a cathode region of said second conductivity type in said layer of epitaxial material between said first and second gate regions, said cathode region being separated from said first and second gate regions and being juxtaposed to said anode region; and forming an anode shorting region of said second conductivity type in said body, said anode shorting region being contiguous with said second major surface of said body and disposed about a portion of said anode region.
Claim 7
Independent Claim
212 words
A method of manufacturing a gate-controlled switch comprising the steps of: providing a body of semiconductor material of a second conductivity type, said body having a first major surface and a second major surface opposite said first major surface; forming a base layer of semiconductor material of a first conductivity type at said first major surface of said body; growing a layer of epitaxial semiconductor material of said second conductivity type overlaying said first major surface of said body; forming a first and second gate regions of said first conductivity type in said layer of epitaxial material, said first and second gate regions being contiguous with said base layer; forming an anode region of said first conductivity type in said body, said anode region being contiguous with said second major surface of said body; forming a cathode region of said second conductivity type in said layer of epitaxial material between said first and second gate regions, said cathode region being separated from said first and second gate regions and being juxtaposed to said anode region; and forming an anode shorting region of said second conductivity type in said body, said anode shorting region being contiguous with said second major surface of said body and disposed about a portion of said anode region.
Claim 8
Independent Claim
197 words
A method of manufacturing a gate-controlled switch comprising the steps of: providing a body of semiconductor material of a second conductivity type, said body having a first major surface and a second major surface opposite said first major surface; forming a base layer of semiconductor material of a first conductivity type at said first major surface of said body; growing a layer of epitaxial semiconductor material of said second conductivity type overlaying said first major surface of said body; forming a gate region and an anode region of said first conductivity type, said gate region being formed in said layer of epitaxial material and being contiguous with said base layer, said anode region being formed in said body and being contiguous with said second major surface of said body; forming a cathode region of said second conductivity type in said layer of epitaxial material, said cathode region being separated from said gate region and being juxtaposed to said anode region; and forming an anode shorting region of said second conductivity type in said body, said anode shorting region being contiguous with said second major surface of said body and disposed about a portion of said anode region.
Claim 9
Independent Claim
197 words
A method of manufacturing a gate-controlled switch comprising the steps of: providing a body of semiconductor material of a second conductivity type, said body having a first major surface and a second major surface opposite said first major surface; forming a base layer of semiconductor material of a first conductivity type at said first major surface of said body; growing a layer of epitaxial semiconductor material of said second conductivity type overlaying said first major surface of said body; forming a gate region and an anode region of said first conductivity type, said gate region being formed in said layer of epitaxial material and being contiguous with said base layer, said anode region being formed in said body and being contiguous with said second major surface of said body; forming a cathode region of said second conductivity type in said layer of epitaxial material, said cathode region being separated from said gate region and being juxtaposed to said anode region; and forming an anode shorting region of said second conductivity type in said body, said anode shorting region being contiguous with said second major surface of said body and disposed about a portion of said anode region.
References Cited (Backward Citations)
US4062032A
Cited
US4032953A
Cited
US4063278A
Cited
US4127863A
Cited
US4170020A
Cited
US4063277A
Cited
US4156248A
Cited
US4137545A
Cited
US4223328A
Cited
US4170502A
Cited
US4511913A
Cited
US4450467A
Cited
US4213067A
Cited
US4443810A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-07-12 | 1992-01-11 | 1992-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-12 | 1996-01-11 | 1996-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-12 | 2000-01-11 | 2000-07-12 | $7700.00 | Window Closed / Lapsed |