Semiconductor devices and methods for making such devices that are especially suited for high-frequency applications are described. The semiconductor devices combine a SIT (or a junction field-effect transistor [JFET]) architecture with a PN super-junction structure. The SIT architecture can be made using a trench formation containing a gate that is sandwiched between thick dielectric layers. While the gate is vertically sandwiched between the two isolating regions in the trench, it is also connected to a region of one conductivity type of the super-junction structure, thereby allowing control of the current path of the semiconductor device. Such semiconductor devices have a lower specific resistance and capacitance relative to conventional planar gate and recessed gate SIT semiconductor devices. Other embodiments are described.