Termination structure for trench DMOS device and method of making the same
First Claim
1. A termination structure provided for a trench DMOS device, comprising:
- a substrate of a first type conductivity;
an epitaxial layer of said first type conductivity over said substrate, said epitaxial layer having a lower doping concentration than said substrate;
a body region of a second type conductivity within said epitaxial layer;
a trench through said body region between an active area and an edge of said substrate;
a gate oxide layer lining said trench and extending to an upper surface of said body region between said trench and said active area;
a passivation layer formed on said gate oxide layer, including sidewalls and a bottom surface of said trench; and
a metal layer covering portions of said passivation layer on the side walls of said trench to expose a part of said passivation layer over the bottom surface of said trench.
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Accused Products
Abstract
Embodiments of the present invention are directed to a termination structure provided for a trench DMOS device to reduce occurrence of current leakage resulting from electric field crowding at the border of the active area and a method of manufacturing the same. In one embodiment, the termination structure for the trench DMOS device comprises a substrate of a first type conductivity and an epitaxial layer of the first type conductivity over the substrate. The epitaxial layer has a lower doping concentration than the substrate. A body region of a second type conductivity is provided within the epitaxial layer. A trench extends through the body region between an active area and an edge of the substrate. A gate oxide layer lines the trench and extends to the upper surface of the body region between the trench and the active area. A passivation layer is formed on the gate oxide layer, including sidewalls and a bottom surface of the trench. A metal layer covers portions of the passivation layer on the side walls of the trench to expose a part of the passivation layer over the bottom surface of the trench.
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Citations
15 Claims
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1. A termination structure provided for a trench DMOS device, comprising:
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a substrate of a first type conductivity;
an epitaxial layer of said first type conductivity over said substrate, said epitaxial layer having a lower doping concentration than said substrate;
a body region of a second type conductivity within said epitaxial layer;
a trench through said body region between an active area and an edge of said substrate;
a gate oxide layer lining said trench and extending to an upper surface of said body region between said trench and said active area;
a passivation layer formed on said gate oxide layer, including sidewalls and a bottom surface of said trench; and
a metal layer covering portions of said passivation layer on the side walls of said trench to expose a part of said passivation layer over the bottom surface of said trench. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A trench DMOS device and a termination structure provided therefor, comprising:
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a substrate of a first type conductivity;
an epitaxial layer of said first type conductivity over said substrate, said epitaxial layer having a lower doping concentration than said substrate;
a body region of a second type conductivity within said epitaxial layer;
a plurality of first type trenches through said body region in an active area of said substrate;
a second type trench through said body region between said active area and an edge of said substrate, said second type trench having a greater width than said first type trenches;
a plurality of contact holes in said body region between said first type trenches;
a plurality of contact regions of said second type conductivity within exposed portions of said body region in said first type trenches;
a plurality of doped regions of said first type conductivity within said body region sandwiched between said contact holes and said first type trenches;
a gate oxide layer lining said first type trenches and said second type trench and extending to upper surfaces of said doped regions in said active area and said body region between said active area and said edge of said substrate;
a plurality of gate electrodes filling said first type trenches;
a passivation layer covering said gate oxide layer and said gate electrodes;
a metal layer provided on said passivation layer and filling said contact holes and said second type trench; and
an opening in said metal layer to expose a part of said passivation layer over a bottom surface of said second type trench, portions of said passivation layer on side walls of said second type trench being covered by said metal layer. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A trench DMOS device, comprising:
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a semiconductor substrate having a trench DMOS active area formed on said substrate and spaced from an edge of said substrate;
a termination area trench disposed between said active area and said edge of said substrate, said termination area trench having a depth extending partially into said substrate, said termination area trench having a bottom surface and side walls disposed between a pair of upper surfaces;
a passivation layer covering said bottom surface and side walls of said termination area trench and said pair of upper surface; and
a metal layer covering portions of said passivation layer on the side walls of said termination area trench to expose a part of said passivation layer over the bottom surface of said termination area trench. - View Dependent Claims (14, 15)
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Specification