Apparatus and method for power MOS transistor

摘要

A method comprises providing a substrate with a second conductivity type, growing a first epitaxial layer having the second conductivity type, growing a second epitaxial layer having a first conductivity type, forming a trench in the first epitaxial layer and the second epitaxial layer, forming a gate electrode in the trench, applying an ion implantation process using first gate electrode as an ion implantation mask to form a drain-drift region, forming a field plate in the trench, forming a drain region in the second epitaxial layer, wherein the drain region has the first conductivity type and forming a source region in the first epitaxial layer, wherein the source region has the first conductivity type, and wherein the source region is electrically coupled to the field plate.

主权项

1. A method comprising:
growing a first epitaxial layer over a substrate; growing a second epitaxial layer over the first epitaxial layer, wherein the first epitaxial layer and the second epitaxial layer have different conductivity types; forming a first trench extending through the second epitaxial layer and partially through the first epitaxial layer; depositing a gate dielectric layer on sidewalls and a bottom of the first trench; depositing a gate electrode layer over the gate dielectric layer; applying a first etching process to the gate electrode layer, wherein as a result of performing the step of applying the first etching process to the gate electrode layer, a top surface of the first epitaxial layer is higher than a top surface of the gate electrode layer; forming a source region underneath a center portion of the bottom of the first trench; applying a second etching process to the gate dielectric layer until the source region is exposed; forming a second trench by removing a center portion of the source region, wherein the second trench extend through the source region and partially through the first epitaxial layer; forming a doped region having a first portion in the first epitaxial layer and a second portion in the substrate; and forming a field plate having a lower portion in the second trench and an upper portion in the first trench.