Power MOSFET and Its Edge Termination
2 Assignments
0 Petitions
Accused Products
Abstract
Improved MOSFET structures and processes, where multiple polysilicon embedded regions are introduced into the n+ source contact area. A top poly Field Plate is used to shield the electric field from penetrating into the channel, so that a very short channel can be used without jeopardizing the device drain-source leakage current. A bottom poly Field Plate is used to modulate the electric field distribution in the drift region such that a more uniform field distribution can be obtained.
59 Citations
22 Claims
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1-2. -2. (canceled)
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3. A semiconductor active device structure, comprising:
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a source region having a first conductivity type, and a current-control structure which controls inversion of portions of a body region having a second conductivity type, to thereby control injection of majority carriers from said source region into a semiconductor drift region which has said first conductivity type; one or more field plates, comprising one or more electrically separated segments within a single insulated trench;
wherein at least one of said segments is electrically floating; andan additional concentration of dopant atoms of said second conductivity type below the bottom of said trench; whereby said field plates smooth the gradation of potential in said drift region adjacent said trench, and said additional concentration of dopant atoms helps reduce depletion of said drift region under conditions of reverse bias. - View Dependent Claims (4, 5, 6, 7, 8, 9)
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10. A semiconductor active device structure, comprising:
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a current-control structure; a semiconductor drift region, through which carriers injected by said current control structure can pass in a predominantly vertical direction; a field-shaping structure, which adjoins at least part of said drift region, and which includes multiple separate conductive segments in a single insulated trench; wherein at least one of said segments is connected to a fixed potential, and at least one of said segments is electrically floating; and wherein different ones of said segments are laterally surrounded by different thicknesses of dielectric material; and an additional concentration of dopant atoms of said second conductivity type below the bottom of said trench; whereby said field plates smooth the gradation of potential in said drift region adjacent said trench, and said additional concentration of dopant atoms helps reduce depletion of said drift region under conditions of reverse bias. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A semiconductor active device structure, comprising:
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a source region, and a current-control structure which controls injection of majority carriers from said source region into a semiconductor drift region which has said first conductivity type; a plurality of field plates, comprising multiple electrically separated electrodes within a single insulated trench; and an additional concentration of dopant atoms of said second conductivity type below the bottom of said trench; said drift region having different net doping concentrations at different depths, such that at least some ones of said field plates laterally adjoin portions of said drift region with different dopant concentrations; whereby said field plates smooth the gradation of potential in said drift region adjacent said trench, and said additional concentration of dopant atoms helps reduce depletion of said drift region under conditions of reverse bias. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification