Surface Cleaning for Si Epitaxy Using Photoexcited Fluorine Gas

Abstract

We have demonstrated surface cleaning for Si epitaxy using photoexcited fluorine gas diluted with argon . We found that cleaning removed native Si oxide, as well as carbon contaminants. The method lowered the surface preannealing temperature needed to grow single‐crystal Si films to 690°C. This preannealing is equivalent to annealing in a hydrogen ambient in conventional chemical vapor deposition. The temperature is low because the native Si oxide is thinned by cleaning. cleaning also reduced interfacial impurities, such as oxygen and carbon, between the epitaxial layer and the substrate for preannealing temperatures above 730°C. We found that cleaning works on bulk features near the Si surface, including the elimination of point defects by fluorine atoms and/or removing carbon and oxygen near the surface. cleaning has good potential for cleaning in Si epitaxy.