High voltage MOSFET with overlapping electrode structure
AssigneeXerox Corporation
InventorRam S. Ronen
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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'S includes 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 control gate and over a channel regon, and relatively thick oxide under a field plate and over a drift region for surface depletion and high voltage field inversion preclusion respectfully. The infra described HVMOSFET includes multiple overlapping field plate and gate electrode able to overcome series resistance associated with HVMOSFET devices having large drift regions.
Claims20
A high voltage metal oxide semiconductor structure in an integrated monolithic array on a substrate having closed geometry for implementation as a driver including a drain region having a relative center axis introduced in the substrate adjacent to the drain region, a source area introduced in the substrate relatively adjacent to the drain area, a channel region introduced in the substrate between the source region and the drain regions, and a drift region introduced in the substrate between the channel region and the drain region, comprising:
- (a) field plate means relatively disposed in a first layer of relatively thick field oxide over the drift region, for application of a potential through the first layer to the drift region for controlling the breakdown voltage as between the source and device regions by contouring the field lines to bend away from the drain region;
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- (b) gate electrode means relatively disposed in a second layer of relatively thin field oxide over the channel region and being spatially overlapped by said field plate means for controlling the potential and turning on and off the current between the source and drain regions and for reduction of series resistance generated in the spatial area between said field plate means and said gate electrode means that it relatively overlaps.
A HVMOSFET driver device and array on a closed geometry integrated monolithic 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 fourth means for function as a drift region;
- (b) field means embedded in a layer of relatively thick oxide above said 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 said first means;
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- (c) gate means embedded in a second layer of relatively thin oxide over said third means and being relatively spatially overlapped by said field means for reduction of series resistance generated in the spatial area between said field means and said gate means that it relatively overlaps and for controlling the potential and turning on and off the current as between said first and second means.
Dependencies are inferred from the claim text.