RIE OF SUB-50 NM HIGH-ASPECT-RATIO PILLARS, RIDGES, AND TRENCHES IN SILICON AND SILICON-GERMANIUM

Sub-50 nm high aspect-ratio pillars, ridges, and trenches have been pa tterned 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 Cl2 and SiCl4 gases, sub-50 nm features with aspect ratios greater than 10 were readily and consi stently achieved. For achieving similar nanostructures in SiGe, an ide ntical gas mixture at lower pressures is required.