Avalanche capability improvement in power semiconductor devices having dummy cells around edge of active area
First Claim
1. A vertical semiconductor power MOSFET device comprising a plurality of semiconductor power cells with each cell comprising a trenched gate surrounded by a source region with first type conductivity in active area encompassed in a body region with second type conductivity above a drain region disposed on a bottom surface of a low-resistivity substrate with first type conductivity, wherein said MOSFET cell further comprising:
- an epitaxial layer of said first conductivity type over said substrate, said epitaxial layer having a lower doping concentration than the substrate;
a first insulating layer serving as gate oxide lining the inner surface of openings for trench gates;
a second insulating layer functioning as thick contact oxide interlayer covering top surface of the epitaxial layer;
a plurality of trench source-body contacts filled with tungsten plugs and opened through the second insulating layer and extending into the body region;
at least one dummy cell without source region formed at the edge of active area near by gate metal pad and gate metal runner.a source metal layer connected to the source regions and the body regions via the trench source-body contacts;
a gate metal layer served as gate metal pad for wire bonding, and connected to gate metal runner;
a drain metal layer formed on a bottom surface of the substrate.
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Accused Products
Abstract
A structure of power semiconductor device having dummy cells around edge of active area is disclosed. The UIS test result of said improved structure shows that failed site after UIS test randomly located in active area which means avalanche capability of the semiconductor power device is enhanced by implementation of the dummy cells.
13 Citations
17 Claims
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1. A vertical semiconductor power MOSFET device comprising a plurality of semiconductor power cells with each cell comprising a trenched gate surrounded by a source region with first type conductivity in active area encompassed in a body region with second type conductivity above a drain region disposed on a bottom surface of a low-resistivity substrate with first type conductivity, wherein said MOSFET cell further comprising:
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an epitaxial layer of said first conductivity type over said substrate, said epitaxial layer having a lower doping concentration than the substrate; a first insulating layer serving as gate oxide lining the inner surface of openings for trench gates; a second insulating layer functioning as thick contact oxide interlayer covering top surface of the epitaxial layer; a plurality of trench source-body contacts filled with tungsten plugs and opened through the second insulating layer and extending into the body region; at least one dummy cell without source region formed at the edge of active area near by gate metal pad and gate metal runner. a source metal layer connected to the source regions and the body regions via the trench source-body contacts; a gate metal layer served as gate metal pad for wire bonding, and connected to gate metal runner; a drain metal layer formed on a bottom surface of the substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A vertical semiconductor power IGBT device comprising a plurality of semiconductor power cells with each cell comprising a trenched gate surrounded by an emitter region with first type conductivity in active area encompassed in a base region with second type conductivity, wherein said IGBT cell further comprising:
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a substrate heavily doped with the second type conductivity; a first epitaxial layer grown on the substrate and heavily doped with the first type conductivity; a second epitaxial layer grown on the first epitaxial layer and lightly doped with the first type conductivity; a first insulating layer serving as gate oxide lining the inner surface of openings for trench gates; a second insulating layer functioning as thick contact oxide interlayer covering top surface of the epitaxial layer; a plurality of trench emitter-base contacts filled with tungsten plugs and opened through the second insulating layer and extending into the body region; at least one dummy cell without emitter region formed at the edge of active area near by gate metal pad and gate metal runner. an emitter metal layer connected to the emitter regions and the base regions via the trench emitter-base contacts; a gate metal layer served as gate metal pad for wire bonding, and connected to gate metal runner; a back metal layer formed on a bottom surface of the substrate. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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Specification