A field effect semiconductor comprises a semiconductor layer having a surface, a first and a second semiconductor region in the semiconductor layer, which are arranged next to one another at the surface of the semiconductor layer, an insulating layer between the first semiconductor region and the second semiconductor region, a semiconductor strip on the surface of the semiconductor layer, which semiconductor strip overlaps the first semiconductor region and the second semiconductor region and adjoins these. A gate overlaps the semiconductor strip at least in the region of the insulating layer. A gate dielectric insulates the gate from the semiconductor strip the first semiconductor region and the second semiconductor region. The semiconductor strip and the gate being formed such that the semiconductor strip is electrically insulating at a first predetermined gate voltage and is electrically conductive at a second predetermined gate voltagero.