Folded channel trench MOSFET

Patent metadata

Field	Value
Publication number	US-10199492-B2
Application number	US-201615364827-A
Country	US
Kind code	B2
Filing date	Nov 30, 2016
Priority date	Nov 30, 2016
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A trench MOSFET device includes a body, region and source region that undulate along a channel width direction of the MOSFET device such that the body region and source region have variations in depth along the channel width direction. The undulations increase a channel width of the MOSFET device.

First claim

What is claimed is:

1. A trench MOSFET device, comprising:
a lightly doped epitaxial layer of a first conductivity type provided on a heavily doped semiconductor substrate of the first conductivity type;
a gate trench filled with a conductive material extending into the lightly doped epitaxial layer;
a body region of a second conductivity type opposite to the first conductivity type provided in portions of the lightly doped epitaxial layer, wherein the body region have a first undulation along a channel width direction; and
a source region of the first conductivity type provided in top portions of the body region, wherein the source region have a second undulation along the channel width direction above the first undulation, wherein a channel width of the MOSFET device is increased with introduction of the first and second undulations wherein the lightly doped epitaxial layer has a third undulation along a channel width direction of the MOSFET device with a depth extending into the semiconductor substrate deeper than other portions of the lightly doped epitaxial layer.

2. The device of claim 1 , wherein the first conductivity type is an N type and the second conductivity type is a P type.

3. The device of claim 1 , wherein the lightly doped epitaxial layer, the body region and the source region have variations in depth along the channel width.

4. The device of claim 1 , wherein the first undulation has a depth extending into the lightly doped epitaxial layer deeper than other portions of the body region.

5. The device of claim 1 , wherein the second undulation has a depth extending into the body region deeper than other portions of the source region.

6. The device of claim 1 , wherein tapered sides of the first and second undulations are at an angle between about 25 degrees and about 90 degrees.

Assignees

• Alpha & Omega Semiconductor

Inventors

• Lui Sik

Classifications

• H10P30/22

  using masks · CPC title

• H10W20/435

  Cross-sectional shapes or dispositions of interconnections · CPC title

• H10W20/069

  by forming self-aligned vias or self-aligned contact plugs · CPC title

• H10W20/056

  by filling conductive material into holes, grooves or trenches · CPC title

• H01L29/66734

  Electricity · mapped topic