Technologies are generally described for reduction of the characteristic on resistance for a transistor device. In some examples, a transistor device may include a source region, a drain region, an n-type epitaxial region between the source and drain regions, a p-type body region, and a deep p-type trench region formed below the body region. The trench region may be configured to charge compensate the n-type epitaxial region. In other examples, the characteristic on resistance may be reduced by replacing the silicon below the body region with lower resistance conductive material. A backside of a wafer that includes the transistor device may be thinned by using a support or carrier on the front side of the wafer to provide mechanical support, and etching trenches in both the substrate silicon and the epitaxial silicon located below the body region of the transistor device. The trenches may be subsequently filled with conductive material.