A power MOSFET includes a semiconductor region extending from a top surface of a semiconductor substrate into the semiconductor substrate, wherein the semiconductor region is of a first conductivity type. A gate dielectric and a gate electrode are disposed over the semiconductor region. A drift region of a second conductivity type opposite the first conductivity type extends from the top surface of the semiconductor substrate into the semiconductor substrate. A dielectric layer has a portion over and in contact with a top surface of the drift region. A conductive field plate is over the dielectric layer. A source region and a drain region are on opposite sides of the gate electrode. The drain region is in contact with the first drift region. A bottom metal layer is over the field plate.