A semiconductor device includes a semiconductor body having a compound semiconductor material on a substrate. The compound semiconductor material has a channel region. A source region extends to the compound semiconductor material. A drain region also extends to the compound semiconductor material and is spaced apart from the source region by the channel region. An insulating region is buried in the semiconductor body between the compound semiconductor material and the substrate in an active region of the semiconductor device. The active region includes the source, the drain and the channel region of the device. The insulating region is discontinuous over a length of the channel region between the source region and the drain region.