Apparatus and method for power MOS transistor

摘要

A MOS transistor comprises a substrate, a first region formed over the substrate, a second region grown from the first region, a third region of formed in the second region, a first drain/source region formed in the third region, a first gate electrode formed in a first trench, a second drain/source region formed in the second region and on an opposite side of the first trench from the first drain/source region and a second trench coupled between the second drain/source region and the second region, wherein the second trench is of a same depth as the first trench.

主权项

1. A method comprising:
forming a buried layer of a second conductivity over a substrate of a first conductivity; forming an epitaxial layer of the second conductive over the buried layer; applying a first etching process to the buried layer and the epitaxial layer to form a first trench and a second trench, wherein a width of the second trench is greater than a width of the first trench; applying a dielectric deposition process to the first trench and the second trench; applying a second etching process to the first trench and the second trench until a dielectric layer in the second trench has been removed; and forming a first gate region in the first trench and a second gate region in the second trench, wherein a bottom surface of the first gate region is higher than a bottom surface of the second gate region.