Damage and contamination free fabrication of thin Si wires with highly controlled feature size

For the precise control of the electrical conductivity in Si ultrafine structures by single ion implantation @II), silicon wires with well-defined patterns have been successfully fabricated without introducing damages and contaminations by combining a focused Si ion beam irradiation with the anisotropic etching of Si crystal in a hydrazine-water solution. A silicon ion beam irradiation enhanced the etching rate of the thermally grown SiO, overlayer on SIMOX (separation by implanted oxygen) Si in HF-water solution. The top-Si was subsequently etched by the hydrazine-water solution with the patterned SiO, film as a mask. It was confirmed by the four point probe measurement that our technique had no influence on the electrical properties of the Si wires.