Germanium Surface Cleaning with Hydrochloric Acid

Abstract

Germanium cleaning is crucial in successful integration of high mobility germanium substrates. HF and HCl do not consume the Ge substrate and do not deteriorate the Ge surface roughness. HF and HCl both show greater than 80% metal recovery rates for most metals. But concentrated HCl solution is more effective in removing the contaminant containing oxide/sub-oxide layers than HF. Therefore HCl is a good candidate for metal contamination removal from Ge surface but other factors such as organic and particle removal and passivation need to be considered simultaneously for an efficient and integrated Ge cleaning process.