A method of manufacturing a semiconductor device includes forming a transistor in a semiconductor substrate having a first main surface. The transistor is formed by forming a source region, forming a drain region, forming a channel region, forming a drift zone, and forming a gate electrode adjacent to at least two sides of the channel region. The channel region and the drift zone are disposed along a first direction parallel to the first main surface, between the source region and the drain region. Forming the semiconductor device further includes forming a conductive layer, a portion of the conductive layer being disposed beneath the gate electrode and insulated from the gate electrode.