Semiconductor devices exhibiting minimum on-resistance
First Claim
1. A semiconductor device comprising:
- a body of semiconductor material having first and second opposed major surfaces and including;
a drift layer of semiconductor material exhibiting a concentration X of dopant impurities therein;
a second layer of semiconductor material between said drift layer and said first major surface;
a trench extending into said body from said first major surface through said second layer and extending a distance Lt into said drift layer to define a pedestal portion of said body having a width W and including portions of said drift and second layers, said drift layer portion of said pedestal having an aspect ratio Lt /W which is greater than or equal to 0.5, an area charge density of WX greater than or equal to ε
EAV /2q, wherein ε
is the permittivity of the semiconductor material, EAV is the electric field strength at avalanche breakdown and q is the electron charge;
means associated with said drift layer portion of said pedestal for diverting electric field lines originating with said dopant impurities of said drift layer portion of said pedestal to thereby increase the voltage supporting potential of said drift layer portion of said pedestal and said device; and
a first main electrode disposed on said first major surface in ohmic contact therewith; and
a second main electrode disposed on said second major surface in ohmic contact therewith;
the main ON-state current path through said device extending between said first and second main electrodes and, when said device is in said ON-state, said pedestal portion of said drift layer is free of inversion layers.
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Accused Products
Abstract
An improved conductivity vertical channel semiconductor device includes an insulated gate electrode disposed adjacent a substantial portion of the voltage supporting region. In response to an appropriate bias, the control electrode couples to the electric field originating on charges within the voltage supporting region to reorient the electric field associated with those charges toward the gate electrode and transverse to the direction of current flow through the device. Improved control of the electric field within the voltage supporting region allows the doping concentration, and hence the conductivity of the channel, to be improved without a concomitant decrease in breakdown voltage. Accordingly, the channel width and cell repeat distance of the improved device can be reduced, allowing for an improved current density to be established throughout an overall device cell structure. The charge control region of the voltage supporting layer exhibits an aspect ratio of 0.5.
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Citations
63 Claims
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1. A semiconductor device comprising:
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a body of semiconductor material having first and second opposed major surfaces and including; a drift layer of semiconductor material exhibiting a concentration X of dopant impurities therein; a second layer of semiconductor material between said drift layer and said first major surface; a trench extending into said body from said first major surface through said second layer and extending a distance Lt into said drift layer to define a pedestal portion of said body having a width W and including portions of said drift and second layers, said drift layer portion of said pedestal having an aspect ratio Lt /W which is greater than or equal to 0.5, an area charge density of WX greater than or equal to ε
EAV /2q, wherein ε
is the permittivity of the semiconductor material, EAV is the electric field strength at avalanche breakdown and q is the electron charge;means associated with said drift layer portion of said pedestal for diverting electric field lines originating with said dopant impurities of said drift layer portion of said pedestal to thereby increase the voltage supporting potential of said drift layer portion of said pedestal and said device; and a first main electrode disposed on said first major surface in ohmic contact therewith; and a second main electrode disposed on said second major surface in ohmic contact therewith; the main ON-state current path through said device extending between said first and second main electrodes and, when said device is in said ON-state, said pedestal portion of said drift layer is free of inversion layers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 62)
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50. A semiconductor device comprising:
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a body of semiconductor material including first, second and third zones having alternating conductivity types, said first and third zones being of one type conductivity, said second zone being of an opposite type conductivity and forming first and second PN junctions with said first and third zones, respectively; said body of semiconductor material having first and second opposed major surfaces, said first major surface being comprised of a portion of said first zone and a portion of said second zone, said body having a substantially vertical trench extending into said body from said first major surface and through said first and second zones and into the third zone to define a pedestal portion of said body including portions of said first, second and third zones, said trench extending a length Lt into said third zone, said third zone portion of said pedestal having a width W and an aspect ratio of Lt /W which is greater than or equal to 0.5 throughout said pedestal; an insulation layer disposed in said trench on said portions of said first, second and third zones exposed by said trench; a gate electrode disposed in said trench adjacent said insulation layer and coextensive with said second zone and extending past said second junction and substantially covering said exposed portion of said third zone; a first main electrode disposed on said first major surface in ohmic contact with said first zone; and a second main electrode disposed on said second major surface in ohmic contact therewith; the main ON-state current path through said device extending between said first and second main electrodes. - View Dependent Claims (51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 63)
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Specification