Trench MOSFET with body region having concave-arc shape
First Claim
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1. A trench MOSFET (Metal Oxide Semiconductor Field Effect Transistor) comprising:
- a substrate of a first conductivity doping type;
an epitaxial layer of said first conductivity doping type over said substrate;
a plurality of trenched gates;
a plurality of source regions of said first conductivity doping type surrounding top portion of said trenched gates;
a plurality of body regions of a second conductivity doping type encompassing said source regions, wherein said body regions have concave-arc shape with respect to top surface of said epitaxial layer;
a plurality of Cds enhancement doped regions of said first conductivity doping type interfaced with said body regions, wherein said Cds enhancement doped regions are formed under said body regions and have higher doping concentration than said epitaxial layer;
a plurality of trenched source-body contacts; and
a plurality of body ohmic contact doped regions of said second conductivity doping type surrounding at least bottoms of said trenched source-body contacts.
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Abstract
A trench Metal Oxide Semiconductor Field Effect Transistor with improved body region structures is disclosed. By forming the inventive body region structures with concave-arc shape with respect to epitaxial layer, a wider interfaced area between the body region and the epitaxial layer is achieved, thus increasing capacitance between drain and source Cds. Moreover, the invention further comprises a Cds enhancement doped region interfaced with said body region having higher doping concentration than the epitaxial layer to further enhancing Cds without significantly impact breakdown voltage.
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12 Claims
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1. A trench MOSFET (Metal Oxide Semiconductor Field Effect Transistor) comprising:
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a substrate of a first conductivity doping type; an epitaxial layer of said first conductivity doping type over said substrate; a plurality of trenched gates; a plurality of source regions of said first conductivity doping type surrounding top portion of said trenched gates; a plurality of body regions of a second conductivity doping type encompassing said source regions, wherein said body regions have concave-arc shape with respect to top surface of said epitaxial layer; a plurality of Cds enhancement doped regions of said first conductivity doping type interfaced with said body regions, wherein said Cds enhancement doped regions are formed under said body regions and have higher doping concentration than said epitaxial layer; a plurality of trenched source-body contacts; and a plurality of body ohmic contact doped regions of said second conductivity doping type surrounding at least bottoms of said trenched source-body contacts. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification