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US4288803A Expired / Lapsed US ⏱️ 0.0 years remaining

High voltage MOSFET with doped ring structure

Assignee: Xerox Corp
•
Filing: 1979-08-08
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Granted: 1981-09-08
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Expires: 1999-08-08
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Abstract

Abstract Integrated monlithic arrays of high voltage metal oxide semiconductor field effect transistors having closed geometry grounded peripheries for interdevice isolation are able to function as drivers that may be switched on and off. The HVMOSFET included DMOS-like structures with separate channel and drift regions, closed geometry configurations with center drains, and split oxide topography having relatively thin oxide under a field plate and over a drift region for surface depletion and high voltage inversion preclusion respectfully. The infra described HVMOSFET includes doping the areas between the field plates, gates and drain electrodes for the purpose of minimizing the problem of series resistance inherent in HVMOSFET'S with spatial gaps between the surface electrodes.

Inventors

  • 👤 Ram S. Ronen

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 21:57
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/111; H10B; H10B20/00; H10D62/00; H10D62/10; H10D62/124; H10D62/126; H10D64/20; H10D64/23; H10D64/251; H10D64/257; H10D64/27; H10D64/311; H10D64/411; H10D64/511; H10D64/514; H10D64/516; H10D64/517; H10D64/519; H10D30/00; H10D30/60; H10D30/601; H10D30/603

Claims Analysis

Total Claims: 27
Claim 1
Independent Claim 226 words
A high voltage MOSFET in an integrated monolithic array on a substrate with a closed geometry configuration including a drain area having a relative center axis introduced in the substrate, a source area introduced in the substate relatively adjacent to the drain area, a channel area introduced in the substrate between the source area and the drain area, and a drift area introduced in the substrate between the channel area and the drain area, comprising: (a) field plate means relatively disposed in a first layer of relatively thick oxide over the drift area for application of a potential through the first layer of thick oxide to the drift area for controlling the breakdown voltage as between the source and drain area by contouring the field lines to bend away from the drain area; (b) gate electrode means relatively disposed in a second layer or relatively thin field oxide over the channel area for controlling the potential and for turning on and off the potential as between the source and drain areas and; (c) ring means implanted in the substrate to be relatively aligned with the spatial gaps occurring between said field plate means and said gate electrode means as doped areas for reducing resistance in the spatial gaps by providing a conductive path for carriers as between said gate electrode means and said field plate means.
Claim 2
Dependent Claim 226 words
A high voltage MOSFET in an integrated monolithic array on a substrate with a closed geometry configuration including a drain area having a relative center axis introduced in the substrate, a source area introduced in the substate relatively adjacent to the drain area, a channel area introduced in the substrate between the source area and the drain area, and a drift area introduced in the substrate between the channel area and the drain area, comprising: (a) field plate means relatively disposed in a first layer of relatively thick oxide over the drift area for application of a potential through the first layer of thick oxide to the drift area for controlling the breakdown voltage as between the source and drain area by contouring the field lines to bend away from the drain area; (b) gate electrode means relatively disposed in a second layer or relatively thin field oxide over the channel area for controlling the potential and for turning on and off the potential as between the source and drain areas and; (c) ring means implanted in the substrate to be relatively aligned with the spatial gaps occurring between said field plate means and said gate electrode means as doped areas for reducing resistance in the spatial gaps by providing a conductive path for carriers as between said gate electrode means and said field plate means.
Claim 3
Dependent Claim 40 words
The high voltage MOSFET of claim 1 wherein said ring means is a relative virtual drain able to enhance injection of electrons as carriers into the drift area when there is a potential as between the drain and source areas.
Claim 4
Dependent Claim 17 words
The high voltage MOSFET of claim 2 wherein said relative virtual drain is relatively heavily N+ doped.
Claim 5
Dependent Claim 17 words
The high voltage MOSFET of claim 2 wherein said relative virtual drain is relatively P type doped.
Claim 6
Dependent Claim 21 words
The high voltage MOSFET of claim 2 wherein said relative virtual drain is relatively neutral conductively implanted as to doping type.
Claim 7
Dependent Claim 18 words
The high voltage MOSFET of claim 2 wherein said relative virtual drain is relatively lightly N type doped.
Claim 8
Dependent Claim 25 words
The high voltage MOSFET of claim 6 wherein said relative virtual drain is relatively lightly N type doped that has been buried as a channel.
Claim 9
Dependent Claim 15 words
The high voltage MOSFET of claim 1 wherein said field plate means is conductivly neutral.
Claim 10
Dependent Claim 17 words
The high voltage MOSFET of claim 1 wherein said ring means are relatively offset but electrically connected.
Claim 11
Dependent Claim 23 words
The high voltage MOSFET of claim 1 wherein said ring means are relatively spatially multiple occurring with independent potentials applied to each thereof.
Claim 12
Dependent Claim 31 words
The high voltage MOSFET of claim 1 wherein said rings are tailored to provide a relatively uniform field drop in the lateral direction of the drain area to the source area.
Claim 13
Dependent Claim 15 words
The high voltage MOSFET of claim 1 wherein said rings are relatively lightly N-type doped.
Claim 14
Dependent Claim 14 words
The high voltage MOSFET of claim 1 wherein said rings are relatively P-type doped.
Claim 15
Dependent Claim 14 words
The high voltage MOSFET of claim 1 wherein said rings are relatively P+type doped.
Claim 16
Dependent Claim 17 words
The high voltage MOSFET of claim 1 wherein said field plate means relatively spatially occur in multiples.
Claim 17
Dependent Claim 16 words
The high voltage MOSFET of claim 1 wherein said field plate means is a polysilicon layer.
Claim 18
Dependent Claim 16 words
The high voltage MOSFET of claim 1 wherein said gate electrode means is a polysilicon layer.
Claim 19
Dependent Claim 19 words
The high voltage MOSFET of claim 1 wherein said field plate means and the drain area are electrically uncoupled.
Claim 20
Dependent Claim 233 words
A HV metal oxide semiconductor FET structure for a driver array having a monolithic integrated closed geometry configuration on a substrate, comprising; (a) first means having a relative center axis implanted in the substrate for function as a drain region, second means implanted in the substrate relatively adjacent to said first means for function as a source region, third means implanted in the substrate relatively interdisposed between said second and first means for function as a channel region, and fourth means implanted in the substrate relatively interdisposed between said third and first means for function as a drift region; (b) field means relatively embedded in a first layer of relatively thick oxide above fourth means for applying a potential to said fourth means for controlling the breakdown voltage as between said second and first means by contouring the field lines to bend away from the drain area, and (c) gate means relatively embedded in a second layer of relatively thin oxide over said third means for controlling the potential and for turning on and off the current between said first and second means; and; (d) ring means relatively disposed in the substrate to be aligned with the gaps occurring between said field means and said gate means as doped areas for reducing resistance in the spatial gaps by providing a conductive path for electrons as between said gate means and said field means.
Claim 21
Dependent Claim 233 words
A HV metal oxide semiconductor FET structure for a driver array having a monolithic integrated closed geometry configuration on a substrate, comprising; (a) first means having a relative center axis implanted in the substrate for function as a drain region, second means implanted in the substrate relatively adjacent to said first means for function as a source region, third means implanted in the substrate relatively interdisposed between said second and first means for function as a channel region, and fourth means implanted in the substrate relatively interdisposed between said third and first means for function as a drift region; (b) field means relatively embedded in a first layer of relatively thick oxide above fourth means for applying a potential to said fourth means for controlling the breakdown voltage as between said second and first means by contouring the field lines to bend away from the drain area, and (c) gate means relatively embedded in a second layer of relatively thin oxide over said third means for controlling the potential and for turning on and off the current between said first and second means; and; (d) ring means relatively disposed in the substrate to be aligned with the gaps occurring between said field means and said gate means as doped areas for reducing resistance in the spatial gaps by providing a conductive path for electrons as between said gate means and said field means.
Claim 22
Dependent Claim 40 words
The HV metal oxide semiconductor FET structure of claim 15 wherein said ring means is a virtual drain able to enhance injection of electrons into said fourth means when there is a relative potential between siad first and second means.
Claim 23
Dependent Claim 20 words
The HV metal oxide semiconductor FET structure of claim 15 wherein said virtual drain is relatively heavily N+ type doped.
Claim 24
Dependent Claim 19 words
The HV metal oxide semiconductor FET structure of claim 19 wherein said virtual drain is relatively P type doped.
Claim 25
Dependent Claim 22 words
The HV metal oxide semiconductor FET structure of claim 19 wherein said virtual drain is relatively neutrally implanted as to doping type.
Claim 26
Dependent Claim 20 words
The HV metal oxide semiconductor FET structure of claim 19 wherein said virtual drain is relatively lightly N type doped.
Claim 27
Dependent Claim 23 words
The HV metal oxide semiconductor FET structure of claim 20 is relatively lightly N type doped that has been buried as a channel.

References Cited (Backward Citations)

US4017883A Cited
US3909320A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1984-09-07 1985-03-09 1985-09-08 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1988-09-07 1989-03-09 1989-09-08 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1992-09-07 1993-03-09 1993-09-08 $7700.00 Window Closed / Lapsed

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