Reactive ion etching of Si SiGe in CF4/Ar and Cl2/BCl3/Ar discharges

The reactive ion etching (RIE) of Si and SiGe in CF4/Ar and Cl-2/BCl3/Ar discharge is investigated as a function of plasma parameters such as power, pressure, and relative composition. We found that the etching rates of Si and SiGe are normally faster in CF4/Ar than in Cl-2/ BCl3/Ar since Si-based chloride has a high boiling point. Using BCl3 containing gases, we can achieve a better etching result when the BCl3 ratio was less than 10% at 60 mTorr 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 etching when the pressure is high and the power is low. (C) 1999 Elsevier Science S.A. All rights reserved.