Method of making quantum well structure with self-aligned gate

Abstract

Quantum well structures are fabricated by use of a process employing a Focused Ion Beam (FIB) scanning in the surface of a semiconductor substrate. The quantum well structures thus fabricated include Resonant Tunneling Transistors (RRTs) and one dimensional quantum wire devices, fabricated in conventional Metal Semiconductor Field Effect Transistors (MESFETs) or in High Electron Mobility Transistors (HEMTs). The RRT comprises a pair of implant barriers in the semiconductor substrate, whereby charge carriers are capable of tunneling through the implant barriers into the quantum well during the state of resonance. The one dimensional quantum wire device comprises a multiplicity of implant barriers disposed in the semiconductor substrate substantially parallel to the travelling direction of the charge carriers. The intersection of the implant barriers and the two dimensional gas (2DEG) inside the HEMT enclose truly one dimensional quantum wells which enable electrons to travel therethrough with high mobility. In addition, the potentials of the quantum wells or quantum wires are controlled by a self-aligned gate, such as a T-gate.