In‐plane‐gated quantum wire transistor fabricated with directly written focused ion beams

A new unipolar electronic device with a quasi‐one‐dimensional (1D) tunable carrier channel defined by directly written focused ion beams has been fabricated and characterized. Special features of the device are simple and rapid fabrication in one single technology step, inherent self‐alignment, and linear instead of planar gates with very low capacitances. High integration as well as ultrahigh speed operation in logical and linear applications are feasible. The striking new aspect of this in‐plane‐gate structure is that the confining electric field is parallel to the two‐dimensional electron gas, and the distorted, insulating region serves as a dielectric. Ballistic 1D transport is observed at low temperatures, and field‐effect transistor operation of the device is demonstrated up to room temperature.