Bidirectional MOSFET with suppressed bipolar snapback and method of manufacture
First Claim
1. A bidirectional trench field effect transistor (FET) device comprising:
- a semiconductor substrate having a surface;
a trench in said semiconductor substrate extending vertically from said surface;
a body region disposed in said semiconductor substrate and laterally adjacent to said trench, said body region being spaced from said surface and having a first conductivity type;
a source region disposed at said surface of said semiconductor substrate between said body region and said surface;
a dielectric layer disposed over said surface of said semiconductor substrate;
a body electrode disposed over said dielectric layer; and
a body contact plug extending through said dielectric layer, said body contact plug interconnecting said body region with said body electrode, and said body contact plug being electrically isolated from said source region.
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Accused Products
Abstract
A bidirectional trench FET device includes a semiconductor substrate, a trench in the substrate extending vertically from the surface of the substrate, and a body region laterally adjacent the trench. A source region is disposed in the semiconductor substrate between the body region and the surface of the substrate. A dielectric layer is disposed over the surface and a body electrode is disposed over the dielectric layer. A body contact plug extends through the dielectric layer to interconnect the body region with the body electrode, and the body contact plug is electrically isolated from the source region. Two separate metal layers are implemented to make multiple body and source contacts electrically isolated from one another throughout the active area of the device. The low resistive path by the body contact plug and the separate metal layers enables suppression of bipolar snapback without losing bidirectional switching capability.
17 Citations
20 Claims
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1. A bidirectional trench field effect transistor (FET) device comprising:
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a semiconductor substrate having a surface; a trench in said semiconductor substrate extending vertically from said surface; a body region disposed in said semiconductor substrate and laterally adjacent to said trench, said body region being spaced from said surface and having a first conductivity type; a source region disposed at said surface of said semiconductor substrate between said body region and said surface; a dielectric layer disposed over said surface of said semiconductor substrate; a body electrode disposed over said dielectric layer; and a body contact plug extending through said dielectric layer, said body contact plug interconnecting said body region with said body electrode, and said body contact plug being electrically isolated from said source region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A bidirectional trench field effect transistor (FET) device comprising:
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a semiconductor substrate having a surface; a trench in said semiconductor substrate extending vertically from said surface; a body region disposed in said semiconductor substrate and laterally adjacent to said trench, said body region being spaced from said surface and having a first conductivity type; a source region disposed at said surface of said semiconductor substrate between said body region and said surface; a dielectric layer disposed over said surface of said semiconductor substrate; a body electrode disposed over said dielectric layer; a body contact plug extending through said dielectric layer and said source region, said body contact plug interconnecting said body region with said body electrode; a dielectric lining surrounding said body contact plug, said dielectric lining electrically isolating said body contact plug from said source region; a source electrode vertically disposed away from said body electrode; and a source interconnect interconnecting said source region with said source electrode, wherein said source electrode and said source interconnect are electrically isolated from said body electrode. - View Dependent Claims (13, 14, 15, 16)
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17. A method of fabricating a bidirectional trench field effect transistor (FET) device having suppressed bipolar snapback, said bidirectional trench FET including a semiconductor substrate having a surface, a trench in said semiconductor substrate extending vertically from said surface, a body region disposed in said semiconductor substrate and laterally adjacent to said trench, said body region being spaced from said surface and having a first conductivity type, and a source region disposed at said surface of said semiconductor substrate between said body region and said surface, and said method comprising:
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disposing a dielectric layer over said surface of said semiconductor substrate; disposing a body electrode over said dielectric layer; forming a body contact plug extending through said dielectric layer to interconnect said body region with said body electrode; and electrically isolating said body contact plug from said source region. - View Dependent Claims (18, 19, 20)
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Specification