Abstract: A high voltage MOSFET device (100) has a well region (113) with two areas. The first area (110) has a high dopant concentration and the second area (112) has a low dopant concentration. Inside the well region a region of a secondary conductivity type (108) is formed. The second area (110) is typically underlying a gate region (105). The lower doping concentration in that area helps to increase the breakdown voltage when the semiconductor device is blocking voltage and helps to decrease the on-resistance when the semiconductor device is in the “on” state. The MOSFET device further has a p-top layer (108) which is disposed on the top surface of the well region and then driven into the well region by annealing the MOSFET device at a high temperature in an inert atmosphere.