A field effect transistor (FET) and fabrication method are disclosed. The FET includes a drift region formed in a substrate. A trench adjoins the drift region and contains at least one control region and a connection region. An inversion channel region is isolated from the control region. A portion of the trench extends to the same depth as a second trench that insulates the FET from other components formed in the substrate. Insulating material is disposed between the trench below the control region and the control region. An insulating layer insulates the FET from the substrate. The trench and/or the connection region may extend into the insulating layer or may be isolated from the insulating layer via the drift region.