GaAs single electron transistors and logic inverters based on Schottky wrap gate structures

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Abstract
Summary form only given. Due to the availability of precisely controllable heteroepitaxy and superb electron transport, III-V compound semiconductor single electron integrated circuits are promising candidates for next generation electronics featuring ultra-small delay-power products near the quantum limit and ultra-high circuit densities. The key issue is to establish single electron transistor (SET) structures that can realize sufficient circuit performance and high-density integration. This paper presents novel GaAs SETs and SET logic inverters utilizing the Schottky wrap gate (WPG) structure (Kasai et al, Jpn. J. Appl. Phys. vol. 36, p. 1678, 1997). The advantages of WPG devices are stronger electron confinement than the traditional split gate structure, device design flexibility, and fabrication process simplicity. In the basic WPG structure, a nanometer-length Schottky gate is wrapped around an etched AlGaAs-GaAs trapezoidal nanowire to strongly confine electrons. In the 2-gate WPG SET structure, complete depletion underneath the WPGs forms double tunnel barriers with a quantum dot (QD) in between. A tighter dot potential control is expected in the 3-gate WPG SET.