RIE of sub-50 nm high aspect-ratio pillars, ridges, and trenches in silicon and silicon-germanium

Abstract

Sub-50 nm high aspect-ratio pillars, ridges, and trenches have been patterned in Si and SiGe using reactive ion etching (RIE) with Cr masks defined by ultra-high resolution electron beam lithography and a lift-off process. Using an optimized mixture of Cl 2 and SiCl 4 gases, sub-50 nm features with aspect ratios greater than 10 were readily and consistently achieved. For achieving similar nanostructures in SiGe, an identical gas mixture at lower pressures is required.