Top-down fabrication of shape controllable Si nanowires based on conventional CMOS process

Shape controllable silicon nanowires (SiNWs) have been fabricated with CMOS compatible top-down fabrication process by carefully designing the oxidation temperature, time, and the original shape of Si wires. Higher oxidation temperature favors the formation of circular SiNWs, since the impact of oxidation retardation on the oxidation rate at sharp corners is reduced, and the discrepancy between the oxidation rates of different SiNW planes is minimized. In our work, high quality circular SiNWs with diameter of 5 nm have been successfully fabricated at high oxidation temperature of 950 °C. Pentagonal, triangular, and circular SiNWs with diameter around 10 nm have also been obtained at 950 °C by controlling the oxidation time and the original shape of the wires.