Method of forming a trench MOSFET with structure having increased cell density and low gate charge
First Claim
1. A method of forming a trench MOSFET device comprising:
- providing semiconductor substrate of first conductivity type;
forming a semiconductor epitaxial layer over said semiconductor substrate, said epitaxial layer being of said first conductivity type and having a lower majority carrier concentration than said substrate;
forming a region of second conductivity type within an upper portion of said semiconductor epitaxial layer, such that an epitaxial region of first conductivity type remains within a lower portion said semiconductor epitaxial layer;
forming a plurality of trench segments in an upper surface of said epitaxial layer, (i) said trench segments extending through the region of second conductivity type and into said epitaxial region of first conductivity type, (ii) each said trench segment being at least partially separated from an adjacent trench segment by a terminating region of said semiconductor epitaxial layer, and (iii) said trench segments defining a plurality of polygonal body regions within said region of second conductivity type;
forming a first insulating layer lining each said trench segment;
forming a plurality of first conductive regions within said trench segments adjacent to the first insulating layer;
forming a plurality of connecting conductive, each of said connecting conductive regions bridging at least one of said terminating regions and connecting one of said first conductive regions to an adjacent first conductive region; and
forming a plurality of source regions of said first conductivity type within upper portions of said polygonal body regions and adjacent said trench segments, said plurality of source regions positioned outside the terminating regions.
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Abstract
A trench MOSFET includes a plurality of trench segments in an upper surface of an epitaxial layer, extending through a second conductivity type region into a first conductivity type epitaxial region, segment at least partially separated from an adjacent segment by a terminating region, and the trench segments defining a plurality of polygonal body regions within the second conductivity type. A first insulating layer at least partially lines each trench and a plurality of first conductive regions are provided within the trench segments adjacent to the first layer. Each of the conductive regions is connected to an adjacent first conductive region by a connecting conductive region, overlying the terminating region, that bridges at least one of the terminating regions and a plurality of first conductivity type source regions are within upper portions of the polygonal body regions and adjacent the trench segments, the source regions positioned outside the terminating regions.
15 Citations
13 Claims
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1. A method of forming a trench MOSFET device comprising:
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providing semiconductor substrate of first conductivity type;
forming a semiconductor epitaxial layer over said semiconductor substrate, said epitaxial layer being of said first conductivity type and having a lower majority carrier concentration than said substrate;
forming a region of second conductivity type within an upper portion of said semiconductor epitaxial layer, such that an epitaxial region of first conductivity type remains within a lower portion said semiconductor epitaxial layer;
forming a plurality of trench segments in an upper surface of said epitaxial layer, (i) said trench segments extending through the region of second conductivity type and into said epitaxial region of first conductivity type, (ii) each said trench segment being at least partially separated from an adjacent trench segment by a terminating region of said semiconductor epitaxial layer, and (iii) said trench segments defining a plurality of polygonal body regions within said region of second conductivity type;
forming a first insulating layer lining each said trench segment;
forming a plurality of first conductive regions within said trench segments adjacent to the first insulating layer;
forming a plurality of connecting conductive, each of said connecting conductive regions bridging at least one of said terminating regions and connecting one of said first conductive regions to an adjacent first conductive region; and
forming a plurality of source regions of said first conductivity type within upper portions of said polygonal body regions and adjacent said trench segments, said plurality of source regions positioned outside the terminating regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification