Power device with improved edge termination
First Claim
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1. A trench gate power MOSFET comprising:
- a drift region of a first conductivity type over a substrate of the first conductivity type;
an active region comprising;
an active well of a second conductivity type extending to a predetermined depth within the drift region;
a plurality of gate trenches extending through the well region; and
a plurality of source regions of the first conductivity type flanking sides of the plurality of gate trenches;
a termination region surrounding the active region, comprising;
a termination well of the second conductivity type extending deeper into the drift region than the active well; and
a resistive element coupled to the termination well, wherein during a UIL switching event upon occurrence of avalanche breakdown in the termination region an avalanche current starts to flow in the termination region, and when the avalanche current reaches a predetermined level the resistive element induces a portion of the avalanche current to flow through the active region and a remaining portion of the avalanche current to flow through the termination region.
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Abstract
A field effect transistor includes an active region and a termination region surrounding the active region. A resistive element is coupled to the termination region, wherein upon occurrence of avalanche breakdown in the termination region an avalanche current starts to flow in the termination region, and the resistive element is configured to induce a portion of the avalanche current to flow through the termination region and a remaining portion of the avalanche current to flow through the active region.
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Citations
12 Claims
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1. A trench gate power MOSFET comprising:
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a drift region of a first conductivity type over a substrate of the first conductivity type; an active region comprising; an active well of a second conductivity type extending to a predetermined depth within the drift region; a plurality of gate trenches extending through the well region; and a plurality of source regions of the first conductivity type flanking sides of the plurality of gate trenches; a termination region surrounding the active region, comprising; a termination well of the second conductivity type extending deeper into the drift region than the active well; and a resistive element coupled to the termination well, wherein during a UIL switching event upon occurrence of avalanche breakdown in the termination region an avalanche current starts to flow in the termination region, and when the avalanche current reaches a predetermined level the resistive element induces a portion of the avalanche current to flow through the active region and a remaining portion of the avalanche current to flow through the termination region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification