Spontaneous production of 10-nm Si structures by plasma etching using self-formed masks

Abstract

When a Si substrate is etched in a SF6 electron cyclotron resonance plasma with the sample maintained at ∼−130 °C, reaction products condense preferentially at nucleation sites on the surface, and automatically form etch masks. Si pillars, ∼10 nm in diameter and ∼0.1 μm high, are then formed. When deposited Au clusters (diameter=1.5±0.7 nm) are used as condensation nuclei, fabricated pillars with an average diameter of 9 nm, standard deviation of 1.5 nm, are formed. This remarkably narrow diameter distribution confirms that the phenomenon is useful in nanostructure formation, and that the process is compatible with electron beam lithography.