Reactive ion etching of Si SiGe in CF4/Ar and Cl-2/BCl3/Ar discharges

The reactive ion etching (RIE) of Si and SiGe in CF4/Ar and Cl-2/BCl3/Ar di scharge is investigated as a function of plasma parameters such as power, p ressure, and relative composition. We found that the etching rates of Si an d SiGe are normally faster in CF4/Ar than in Cl-2/ BCl3/Ar since Si-based c hloride has a high boiling point. Using BCl3 containing gases, we can achie ve a better etching result when the BCl3 ratio was less than 10% at 60 mTor r and 95 W. We also selectively etched Si0.87Ge0.13 on Si by CF4 containing gas mixtures. In 2CF(4)/3Ar discharges, we can achieve a high selective et ching when the pressure is high and the power is low. (C) 1999 Elsevier Sci ence S.A. All rights reserved.