A semiconductor device fabrication method includes forming first and second spaced apart base regions and source regions in a substrate with a portion of a drift region therebetween. The method further includes forming at least a first trench extending laterally through the base region, the drift region and the source region, the first trench extending vertically partially through the source region. The method also includes forming a first oxide layer over the trenched upper surface, and forming a polysilicon layer over the first oxide layer. The polysilicon layer is patterned to form the gate conductor, and a drain contact is formed on a bottom surface of the semiconductor substrate.