Development of a silicon-based quantum cellular automata cell

Keywords:
quantum cellular automata, Si, MOS technology, single-electron transistor, phosphorous implantation

Abstract:
Quantum-dot cellular automata (QCA) [1] represent a potential paradigm shift in computation, offering elegant solutions to the critical problems of device density, interconnection and power dissipation. To date QCA cells have been experimentally demonstrated in Al systems [2] and magnetic dot systems [3], with promising results also in GaAs quantum dot systems [4]. Here we report the experimental demonstration [5] of a basic QCA cell in a phosphorus-doped silicon system. Si-based systems offer advantages including compatibility with scalable Si-MOS technologies, together with great potential for effective cell size reduction, possibly leading to room-temperature operation of single donor Si-based QCA [6].The QCA device studied here consisted of two pairs of metallic dots, separated from source and drain reservoirs by tunnel barriers. The metallic regions were formed by low-energy (14 keV) phosphorous ion implantation through a nanoscale mask defined using electron beam lithography. Metallic gates used to control the electrostatic potential of the dots, along with Al-Al2O3 single-electron transistors used for QCA cell state-readout, were fabricated on the surface of this structure, isolated from the dots and reservoirs by a 5nm layer of SiO2. The device was operated in a dilution refrigerator at a base temperature of 50mK. QCA operation was demonstrated by the switching of a single electron between output dots, controlled by a single electron switching in the input (driver) dots. Results of the measurements are in excellent agreement with modelling [7].

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Nanotech 2006 Conference Program Abstract