Direct writing of silicon nanostructures using liquid-phase electron beam induced deposition of hydrosilanes.

Solid Si (wafer) and gaseous Si (silane) are generally used as starting materials for fabricating Si devices. In this study, a liquid precursor (liquid-phase hydrosilane) for semiconducting Si, called liquid Si (liq-Si), was synthesized to establish a liquid pathway for fabricating Si. Although the liquid-to-solid Si conversion can be induced by heating at 400 °C, conversion without heating was realized herein by electron-beam (EB) irradiation. This study is the first to irradiate liq-Si with EB. Size-controllable Si nanodots, with diameters of the order of 100 nm, were directly deposited at any point by liquid-phase electron-beam-induced deposition (LP-EBID) with a beam diameter of 50 nm. This approach yielded less-contaminated deposits at the detection limit of energy-dispersive x-ray spectroscopy, as opposed to typical EBID, wherein carbon impurities up to 90% are found. The processing resolution of LP-EBID is potentially 1 nm or less. Therefore, this non-heating deposition technique realizes the direct writing of Si nanostructures and would be a powerful tool for Si nanofabrication.