High voltage field effect transistors with superjunctions and method of making the same

Abstract

A field effect transistor includes a semiconductor channel having a doping of a first conductivity type, a gate structure overlying the semiconductor channel, a source region and a drain region, a source-side extension region including a source-side-extension plate portion and source-side-extension rail portions that overlie the source-side-extension plate portion, source-side counter-doped rails having a doping of the first conductivity type, a drain-side extension region including a drain-side-extension plate portion and drain-side-extension rail portions that overlie the drain-side-extension plate portion, and drain-side counter-doped rails interlaced with the drain-side-extension rail portions. A first superjunction structure is provided between the source-side counter-doped rails and the source-side extension region. A second superjunction structure is provided between the drain-side counter-doped rails and the drain-side extension region.