Patent ID: 7691711

Claim:
A method of forming a vertical MOSFET device, the method comprising: forming a first trench within a substrate of a first polarity type, the first trench generally defining a well region of a second polarity type opposite the first polarity type; growing a first epitaxial layer of the second polarity type over the substrate and sidewall surfaces of the first trench, the first epitaxial layer comprising a well layer; growing a second epitaxial layer of the first polarity type over the well layer of the second polarity type, the second layer comprising a source contact layer; forming a second trench through the source contact layer and at least through a portion of the well layer; growing a third epitaxial layer of the second polarity type over the source contact layer so as to refill the second trench; and planarizing at least the first and second epitaxial layers so as to expose an upper surface of the substrate, wherein a top surface of the third epitaxial layer is substantially coplanar with a top surface of the source contact layer prior to a subsequent ohmic contact formation therebetween.