Simulation of a Ballistic GAAFET Based on AlXGa1–XAs Quantum Wire

A ballistic field-effect transistor with a one-dimensional conducting channel inside an all-around-gate is considered, namely, a quantum-barrier field-effect transistor with a Schottky barrier in the conducting channel based on AlXGa1–XAs quantum wire inside a cylindrical gate. Optimization of the design and topological parameters of such a transistor is carried out. For its conducting channel, ranges of length and diameter values are determined at which the maximum saturation current and ultimate possible values of channel conductivity and subthreshold swing are practically achieved. A technique for determining the optimal change in the fraction of aluminum in the semiconductor along the transistor channel is considered, which, in contrast to a typical field-effect transistor with a Schottky barrier in the conducting channel, ensures both complete suppression of the quantum barrier for electrons by a positive gate voltage and the minimum possible electrical resistance of the conducting channel. The output and transfer current-voltage characteristics of a transistor based on an AlXGa1–XAs quantum wire with optimal geometry are calculated within the framework of the developed combined physical and mathematical model describing the electron transport in its conducting channel taking into account the nonparabolicity of the semiconductor band structure, the dominant phonon mechanisms of charge carrier scattering, quantum-dimensional effects and such secondary quantum effects as collisional broadening and shift of particle energy levels in the one-dimensional conducting channel of the transistor.