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US4217599A Expired / Lapsed US ⏱️ 0.0 years remaining

Narrow channel MOS devices and method of manufacturing

Assignee: Maxim Integrated Products Inc
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Filing: 1977-12-21
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Granted: 1980-08-12
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Expires: 1997-12-21
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Abstract

Abstract Improved, high performance MOS transistors are provided by a method that includes providing an oxygen-impermeable mask on a selected region of a semiconductor substrate, oxidizing the unmasked portion of the surface to provide a thick oxide at least partially recessed in the substrate, which layer includes a smoothly tapered beak that extends between the margin of the mask and the underlying silicon surface, and, after removing the mask, implanting a selected impurity in the substrate beneath the selected region to form a thin impurity layer that terminates at a sloped portion of the substrate formed by the oxidation step.

Inventors

  • 👤 Shuichi Sato
  • 👤 Tadanori Yamaguchi
  • 👤 Arthur D. Ritchie

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-26 04:33
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/64; H10D30/65; H10D30/01; H10D30/021; H10D30/028; H10D30/0281; H10D30/0287; H10D30/0289; H10D62/00; H10D62/10; H10D62/17; H10D62/213; H10D62/221; H10D62/235; H10D62/292; H10D62/351; H10D62/357; H10D62/364; H10D62/378; H10P; H10P14/00; H10P14/60; H10P14/61; H10D62/117; H10D62/13; H10D62/149; H10D62/151; H10D64/00; H10D64/20; H10D64/23; H10D64/251; H10D64/256; H10D64/27; H10D64/311; H10D64/411; H10D64/511; H10D64/512; H10D64/513

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 115 words
A field effect transistor comprising: a body of semiconductor material having a nonplanar surface that includes adjacent areas of relatively higher and lower elevation joined by a slope, a first region of one conductivity type in said body underlying said higher elevation area, a second region of the same conductivity type in said body underlying said lower elevation area, one of said first and second regions serving as a source region and the other as a drain for said transistor, and an implanted layer of the opposite conductivity type disposed intermediate said first and second regions, said layer having an upturned margin terminating at said slope and serving as a channel region for said transistor.
Claim 2
Dependent Claim 115 words
A field effect transistor comprising: a body of semiconductor material having a nonplanar surface that includes adjacent areas of relatively higher and lower elevation joined by a slope, a first region of one conductivity type in said body underlying said higher elevation area, a second region of the same conductivity type in said body underlying said lower elevation area, one of said first and second regions serving as a source region and the other as a drain for said transistor, and an implanted layer of the opposite conductivity type disposed intermediate said first and second regions, said layer having an upturned margin terminating at said slope and serving as a channel region for said transistor.
Claim 3
Dependent Claim 35 words
The transistor of claim 1, further comprising: an insulating layer covering at least the portion of said slope that includes the termination of said implanted layer, and a gate electrode disposed on said insulating layer.
Claim 4
Dependent Claim 21 words
The transistor of claim 1, wherein said channel and drain regions are spaced apart to provide a drift region between them.
Claim 5
Dependent Claim 151 words
An integrated circuit structure comprising: a semiconductor sustrate having a laterally extending upper surface, said surface including a first, higher elevation portion and a second, lower elevation portion joined to the first by a slope, a first region of one conductivity type extending into said substrate at said first surface portion, a second region of the same conductivity type extending into said substrate at said second surface portion, one of said first and second regions serving as a source region and the other as a drain region of a field effect device in said structure, a thin implanted layer of the opposite conductivity type disposed intermediate said first and second regions, said layer having an upwardly-extending portion that terminates at said slope and serves as a channel region for said device, and a gate electrode disposed overlying at least the portion of said slope that includes the termination of said layer.
Claim 6
Dependent Claim 151 words
An integrated circuit structure comprising: a semiconductor sustrate having a laterally extending upper surface, said surface including a first, higher elevation portion and a second, lower elevation portion joined to the first by a slope, a first region of one conductivity type extending into said substrate at said first surface portion, a second region of the same conductivity type extending into said substrate at said second surface portion, one of said first and second regions serving as a source region and the other as a drain region of a field effect device in said structure, a thin implanted layer of the opposite conductivity type disposed intermediate said first and second regions, said layer having an upwardly-extending portion that terminates at said slope and serves as a channel region for said device, and a gate electrode disposed overlying at least the portion of said slope that includes the termination of said layer.
Claim 7
Dependent Claim 19 words
The structure of claim 4, further including an insulating layer interposed between said gate electrode and said substrate slope.
Claim 8
Dependent Claim 24 words
The structure of claim 5, wherein said channel and drain regions are spaced apart a distance sufficient to provide a drift region between them.
Claim 9
Dependent Claim 39 words
The structure of claim 4, wherein said implanted layer is provided by ion implantation through an oxide layer formed on said slope, said layer having a thickness that increases progressively from the top to the bottom of the slope.
Claim 10
Dependent Claim 23 words
The structure of claim 4, wherein said first and second regions are of n-type conductivity, and said implanted layer is of p-type conductivity.
Claim 11
Dependent Claim 25 words
The structure of claim 4, wherein said first region serves as the source region, and said channel-forming implanted layer is disposed adjacent said first region.
Claim 12
Dependent Claim 170 words
An integrated circuit structure comprising: a semiconductor substrate having a laterally extending upper surface, said surface including an elevated plateau portion joined by a slope to an adjacent field portion, a first region of one conductivity type in said substrate at least partially underlying said plateau portion of the upper surface, a second region of the same conductivity type in said substrate at least partially underlying said field portion of said surface, one of said first and second regions serving as a source region and the other as a drain region for a field effect device incorporated in said structure, a thin implanted layer of the opposite conductivity type disposed intermediate said first and second regions, said layer having an upwardly extending marginal portion that terminates at said slope and serves as a channel region for said device, an insulating layer covering at least the portion of said slope that includes the termination of said implanted layer, and a gate electrode disposed on said insulating layer overlying said channel region.
Claim 13
Dependent Claim 170 words
An integrated circuit structure comprising: a semiconductor substrate having a laterally extending upper surface, said surface including an elevated plateau portion joined by a slope to an adjacent field portion, a first region of one conductivity type in said substrate at least partially underlying said plateau portion of the upper surface, a second region of the same conductivity type in said substrate at least partially underlying said field portion of said surface, one of said first and second regions serving as a source region and the other as a drain region for a field effect device incorporated in said structure, a thin implanted layer of the opposite conductivity type disposed intermediate said first and second regions, said layer having an upwardly extending marginal portion that terminates at said slope and serves as a channel region for said device, an insulating layer covering at least the portion of said slope that includes the termination of said implanted layer, and a gate electrode disposed on said insulating layer overlying said channel region.

References Cited (Backward Citations)

US4091405A Cited
US4074301A Cited
US4055444A Cited
US4029522A Cited
US4078947A Cited
US4084175A Cited
US4044452A Cited
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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1983-08-12 1984-02-11 1984-08-12 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1987-08-12 1988-02-11 1988-08-12 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1991-08-12 1992-02-11 1992-08-12 $7700.00 Window Closed / Lapsed

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