A semiconductor transistor is formed on a substrate of a first conductivity type. The substrate has a main surface. An ion well of the second conductivity type is disposed in the substrate. A source region and a drain region spaced apart from the source region are disposed within the ion well. The source region and the drain region have the first conductivity type. An epitaxial channel layer of the first conductivity type is grown from the main surface of the substrate and is disposed between the source region and the drain region. A gate is disposed on the epitaxial channel layer. A gate dielectric layer is disposed between gate and the epitaxial channel layer.