Single-electron transistor structures based on silicon-on-insulator silicon nanowire fabrication by scanning probe lithography and wet etching

We propose a promising fabrication technology for single-electron transistors based on a silicon-on-insulator (SOI) nanowire fabricated by scanning probe lithography and KOH wet etching. The 10-nm-wide and 10-nm-high silicon nanowire is defined by scanning probe lithography and KOH wet etching process technology. Along the [100] direction on a (100) SOI silicon wafer, local oxidation was performed in ambient using highly doped Si cantilevers with a resistivity of 0.01-0.0025 Omega cm and a commercial atomic force microscope/scanning tunneling microscope instrument. Using the oxide pattern as a Si etching mask, the Si substrate was dipped in aqueous KOH solution, in which unoxidized regions are selectively etched by aqueous KOH orientation-dependent etching. The silicon nanowire was obtained by well-controlled overetching of 34 wt % at 40 degreesC for 50 s. The top gate, back gates and contact pads were defined by photolithography and dry etching. Statistics showing the reproducibility of this technique are also demonstrated. (C) 2002 American Vacuum Society.