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US 8,575,700 B2Granted
Charge-balance power device comprising columnar structures and having reduced resistance
AssigneeSTMicroelectronics S.r.l.
InventorFabio Zara
Life of this patent
Estimating the term…
Abstract
A charge-balance power device formed in an epitaxial layer having a first conductivity type and housing at least two columnar structures of a second conductivity type, which extend through the epitaxial layer. A first surface region of the second conductivity type extends along the surface of the epitaxial layer on top of, and in contact with, the columns, and a second surface region of the first conductivity type extends within the first surface region, and also faces the surface of the epitaxial layer. The columns extend at a distance from one another from the first surface region so as to delimit between them an epitaxial portion that defines a current path so as to reduce the on-resistivity of the device.
Claims18
A charge-balance power device, comprising:
- a semiconductor layer having a first conductivity type and a surface;
- at least two columnar structures of a second conductivity type, extending through said semiconductor layer;
- a first surface region of the second conductivity type, extending along said surface, on top of and in contact with each of the at least two columnar structures;
- and
- a second surface region of the first conductivity type, extending within the first surface region and facing said surface and disposed between portions of the first surface region that are in contact with each of the at least two columnar structures,
- wherein the columnar structures extend from the first surface region and are separated at a distance from each other such that the columnar structures are disposed under the first surface region and not under the second surface region.
3 more elements
A power device, comprising:
- a substrate having a first conductivity type;
- a semiconductor layer formed on the substrate and having the first conductivity type and first and second surfaces, the second surface being defined as a junction between the semiconductor layer and the substrate;
- body regions having a second conductivity type formed in the semiconductor layer spaced apart from one another and extending from the first surface of the semiconductor layer;
- source regions formed in the body regions;
- at least two columnar structures formed in the semiconductor layer, the columnar structures being spaced apart from one another and each of the at least two columnar structures having the second conductivity type and in contact with and extending from a corresponding one of the body regions towards the second surface of the semiconductor layer, each columnar structure spaced apart from the source regions such that no columnar structure is disposed directly under any one of the source regions a gate structure formed on the first surface of the semiconductor layer and being positioned between and partially overlapping the body regions;
- and a drain contact formed on a surface of the substrate opposite the surface on which the semiconductor layer is formed.
3 more elements
An electronic system, comprising:
- electronic circuitry operable to perform a desired function, the electronic circuitry including at least one power device and at least some of the power devices comprising,
- a substrate having the first conductivity type;
- a semiconductor layer formed on the substrate and having the first conductivity type and first and second surfaces, the second surface being defined as the junction between the semiconductor layer and the substrate;
- body regions having a second conductivity type formed in the semiconductor layer spaced apart from one another and extending from the first surface of the semiconductor layer;
- source regions formed in the body regions;
- at least two columnar structures formed in the semiconductor layer, the columnar structures being spaced apart from one another and the each of the at least two columnar structures having the second conductivity type and in contact with and extending from a corresponding one of the body regions towards the second surface of the semiconductor layer, the at least two columnar structures arranged staggered to one another with respect to a first direction and partially facing one another with respect to a second direction transversal to the first direction such that no columnar structure is disposed directly under any one of the source regions;
- a gate structure formed on the first surface of the semiconductor layer and being positioned between and partially overlapping the body regions;
- and a drain contact formed on a surface of the substrate opposite the surface on which the semiconductor layer is formed.
5 more elements
A method of forming a power device in a semiconductor, comprising:
- a substrate having the first conductivity type;
- a semiconductor layer formed on the substrate and having the first conductivity type and first and second surfaces, the second surface being defined as the junction between the semiconductor layer and the substrate;
- body regions having a second conductivity type formed in the semiconductor layer spaced apart from one another and extending from the first surface of the semiconductor layer;
- source regions formed in the body regions;
- at least two columnar structures formed in the semiconductor layer, the columnar structures being spaced apart from one another and having the second conductivity type, the at least two columnar structures in contact with and extending from a corresponding one of the body regions towards the second surface of the semiconductor layer, the at least two columnar structures arranged staggered to one another with respect to a first direction and partially facing one another with respect to a second direction transversal to the first direction such that no columnar structure is disposed directly under any one of the source regions;
- a gate structure formed on the first surface of the semiconductor layer and being positioned between and partially overlapping the body regions;
- and a drain contact formed on a surface of the substrate opposite the surface on which the semiconductor layer is formed.
4 more elements
Dependencies are inferred from the claim text.