High-density silicon nanowire growth from self-assembled Au nanoparticles

We report a method to grow high-density silicon nanowires (SiNWs) from self-assembled Au nanoparticles on SiO"2 surfaces. A high-vacuum electron-beam metal evaporation system was utilized for the deposition of the particles. The size of the particles is about 5-10nm with a relatively tight distribution and a homogeneous separation. The Au nanoparticles were used as growth mediating impurities for the vapor-liquid-solid growth of SiNWs utilizing a low pressure chemical vapor deposition system and silane as Si source. The diameter of the SiNWs can be varied between 20 and 250nm by changing the growth conditions. It was found that the SiNW diameter increases with increasing silane pressure and also with increasing temperature. Local growth of SiNWs is demonstrated using optical and electron-beam lithography. The CVD-based SiNW growth from self-assembled nanoparticles in combination with top-down lithography may form the bridge between top-down and bottom-up processing for future devices.