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US 7,063,975 B2Granted
Shallow trench power MOSFET and IGBT
AssigneeIXYS Corporation
InventorsVladimir Tsukanov, Nathan Zommer
Life of this patent
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Abstract
A power semiconductor device includes a substrate having an upper surface and a lower surface. The substrate has a trench. First and second doped regions are provided proximate the upper surface of the substrate. A first source region is provided within the first doped region. A second source region is provided within the second doped region. A gate is provided between the first and second source regions. The gate includes a first portion extending downward into the trench. A depth of the trench is no more than a depth of the first doped region.
Claims5
A method for fabricating a power semiconductor device, comprising:
- forming a shallow trench on a substrate having a first surface and a second surface, the shallow trench having a first depth and a width, the width of the shallow trench being greater than the first depth of the shallow trench;
- forming a doped region provided proximate the first surface of the substrate and having a second depth;
- forming a source region provided within the doped region and proximate the first surface;
- and
- forming a gate structure provided adjacent the source region, the gate structure including a first portion provided within the shallow trench and a second portion provide outside of the trench,
- wherein the first portion includes a lateral extension and that is parallel to the first and second surface of the substrate,
- wherein the lateral extension of the first portion is at least 2.5 times greater than the first depth of the shallow trench,
- wherein forming the shallow trench includes:
- etching the substrate to form an intermediate trench having a third depth that is less than the first depth;
- forming a first oxide layer within the intermediate layer;
- and
- removing the oxide layer formed within the intermediate trench, wherein a resulting trench from the removal of the oxide layer has a fourth depth that is greater than the third depth.
9 more elements
A method for fabricating a power semiconductor device, comprising:
- forming a shallow trench on a substrate having a first surface and a second surface, the shallow trench having a first depth and a width, the width of the shallow trench being greater than the first depth of the shallow trench;
- forming a doped region provided proximate the first surface of the substrate and having a second depth;
- forming a source region provided within the first doped region and proximate the first surface;
- and
- forming a gate structure provided adjacent the source region, the gate structure including a first portion provided within the shallow trench and a second portion provide outside of the trench,
- wherein forming the shallow trench includes:
- etching the substrate to form an intermediate trench having a third depth that is less than the first depth;
- forming a first oxide layer within the intermediate layer;
- and
- removing the oxide layer formed within the intermediate trench, wherein a resulting trench from the removal of the oxide layer has a fourth depth that is greater than the third depth.
7 more elements
A power semiconductor device, comprising:
- a substrate having an upper surface and a lower surface, the substrate having a trench;
- first and second doped regions provided proximate the upper surface of the substrate;
- a first source region provided within the first doped region;
- a second source region provided within the second doped region;
- and
- a gate provided between the first and second source regions, the gate including a first portion extending laterally within the trench, wherein a depth of the trench is no more than a depth of the first doped region,
- wherein the gate has a lateral extension and a vertical extension, the lateral extension being substantially greater than the vertical extension to reduce the curvature of equi-potential lines that are defined below the gate and the first and second dope regions,
- wherein the gate is formed by etching the substrate to form an intermediate trench having a third depth that is less than the depth of the trench, forming a first oxide layer within the intermediate layer, and removing the oxide layer formed within the intermediate trench,
- wherein a resulting trench from the removal of the oxide layer has a fourth depth that is greater than the third depth.
6 more elements
Dependencies are inferred from the claim text.