Semiconductor device
First Claim
Patent Images
1. A trench MOSFET comprising:
- an epitaxial layer;
a body region on the epitaxial layer, the body region and the epitaxial layer forming a first interface;
a trench;
a trench bottom oxide in the trench; and
polysilicon in the trench, the trench bottom oxide and the polysilicon forming a second interface;
wherein the first and second interfaces are substantially aligned or are at substantially the same level, such that an overlap between the body region and the trench bottom oxide is less than about 25 nm;
wherein a surface of the trench bottom oxide which is in contact with polysilicon is convex;
wherein the trench bottom oxide comprises a first trench bottom oxide portion occupying substantially the entire width of the trench, and a second trench bottom oxide portion directly on the first trench bottom oxide portion, the second trench bottom oxide portion occupying substantially less than the entire width of the trench;
wherein the second trench bottom oxide portion occupies a central portion of the trench with respect to the width of the trench; and
wherein the second trench bottom oxide portion extends to the top of the trench.
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Accused Products
Abstract
A trench MOSFET including: an epitaxial layer; a body region on the epitaxial layer, the body region and the epitaxial layer forming a first interface; a trench; a trench bottom oxide in the trench; and polysilicon in the trench, the trench bottom oxide and the polysilicon forming a second interface; where the first and second interfaces are substantially aligned or are at substantially the same level.
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Citations
10 Claims
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1. A trench MOSFET comprising:
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an epitaxial layer; a body region on the epitaxial layer, the body region and the epitaxial layer forming a first interface; a trench; a trench bottom oxide in the trench; and polysilicon in the trench, the trench bottom oxide and the polysilicon forming a second interface; wherein the first and second interfaces are substantially aligned or are at substantially the same level, such that an overlap between the body region and the trench bottom oxide is less than about 25 nm; wherein a surface of the trench bottom oxide which is in contact with polysilicon is convex; wherein the trench bottom oxide comprises a first trench bottom oxide portion occupying substantially the entire width of the trench, and a second trench bottom oxide portion directly on the first trench bottom oxide portion, the second trench bottom oxide portion occupying substantially less than the entire width of the trench; wherein the second trench bottom oxide portion occupies a central portion of the trench with respect to the width of the trench; and wherein the second trench bottom oxide portion extends to the top of the trench. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of manufacturing a semiconductor device comprising:
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forming a first trench bottom oxide portion occupying substantially the entire width of a trench; forming at least one spacer in the trench and on the first trench bottom oxide portion; and
thereafterforming a second trench bottom oxide portion on the first trench bottom oxide portion, the second trench bottom oxide portion occupying; substantially less than the entire width of the trench, a central portion of the trench with respect to the width of the trench, and extending to the top of the trench; and using the at least one spacer so as to form the second trench bottom oxide portion in a self-aligned manner. - View Dependent Claims (9)
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10. A trench MOSFET comprising:
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an epitaxial layer; a body region on the epitaxial layer, the body region and the epitaxial layer forming a first interface; a trench; a trench bottom oxide in the trench; and polysilicon in the trench, the trench bottom oxide and the polysilicon forming a second interface; wherein there is no overlap between the body region and the trench bottom oxide, and the distance between the body region and the trench bottom oxide along a line defined by the trench side wall is less than about 0.2 μ
m;wherein a surface of the trench bottom oxide which is in contact with polysilicon is convex; wherein the trench bottom oxide comprises a first trench bottom oxide portion occupying substantially the entire width of the trench, and a second trench bottom oxide portion directly on the first trench bottom oxide portion, the second trench bottom oxide portion occupying substantially less than the entire width of the trench; wherein the second trench bottom oxide portion occupies a central portion of the trench with respect to the width of the trench; and wherein the second trench bottom oxide portion extends to the top of the trench.
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Specification