Patent ID: 6989567

Claim:
A semiconductor transistor structure comprising: a substrate having an epitaxial layer of a first conductivity type; a source region extending from the surface of the epitaxial layer of a second conductivity type; a drain region within said epitaxial layer of a second conductivity type; a channel located between said drain and source regions; a gate arranged above said channel; wherein said drain region comprises: a first region of said second conductivity type for establishing a contact with an electrode; a second region of said second conductivity type being less doped than said first region being buried within said epitaxial layer and extending from said first region horizontally in direction towards said gate; a third region being of said second conductivity type less doped than said second region and extending vertically from the surface of said epitaxial layer and horizontally from said second region until under said gate; a top layer of said first conductivity type extending from the surface of said epitaxial layer to said second region; and a bottom layer of said first conductivity type extending from said second region into said epitaxial layer.