Patent ID: 7323747

Claim:
A lateral semiconductor device formed on a semiconductor layer connected to a support substrate through a buried insulating film, comprising: a body region of a first conductive type formed on the semiconductor layer; a drift region of a second conductive type wholly surrounding the body region, the drift region being adjacent to or separated from the body region; a drain region of a second conductive type that is separated from the body region and is in contact with the drift region; a source region of a second conductive type that is formed in the body region and separated from an end portion of the body region; an insulating film formed on the semiconductor layer and covering at least a range from an end portion of the source region to an end portion of the drain region; a gate electrode covering a range from an upper side of the end portion of the source region to an upper side of the drift region through the insulating film; and electrodes formed on the source region, the body region and the drain region, wherein the body region has a planar shape formed by at least a central portion having a straight shape and end portions each having a substantially semicircular shape, and the gate electrode and the source region are not adjacent to each other through the insulating film in the end portions.