Characterization of precisely width-controlled Si quantum wires fabricated on SOI substrates

Silicon quantum wire structures with precisely controlled widths have been successfully fabricated on an SOI substrate by an anisotropic etching technique. The width of the wires does not depend on the lithography limit but solely on the thickness of the Si film of the SOI substrate. It is demonstrated that the wires are straight even if the lithography patterns are fluctuated. The minimum width is estimated to be less than 10 nm. This technique has been applied to fabricating a quantum wire FET, which shows fine peaks in drain current as a function of the gate voltage at low temperatures due to the Coulomb blockade of the single electron tunneling. The oscillations remain even at room temperature.