SI SINGLE-ELECTRON TRANSISTORS ON SIMOX SUBSTRATES

A Si single electron transistor (SET) was fabricated by converting a o ne-dimensional Si wire on a SIMOX substrate into a small Si island wit h a tunneling barrier at each end by means of pattern-dependent oxidat ion. Since the size of the Si island was as small as around 10 nm owin g to this novel technique. the total capacitance of the SET was reduce d to a value on the order of 1 aF, which guarantees the conductance os cillation of the SET even at room temperature. Furthermore, a linear r elation between the designed wire length and the gate capacitance of S ETs was obtained, which clearly indicates that the single island was a ctually Formed in the middle of the one dimensional Si wire. These res ults were achieved owing to the highly reproducible fabrication proces s based on pattern dependent oxidation of SIMOX-Si layers. In addition , the fluctuation of the electrical characteristics of the SETs was st udied in relation to the wire size fluctuations. It was found that the fluctuation is caused predominantly by the roughness of the sidewall surface of the resist pattern.