Low temperature RPCVD epitaxial growth of Si1−xGex using Si2H6 and Ge2H6

The growth of intrinsic SiGe and, n- and p-type doping of Si and SiGe layers was studied using a Reduced Pressure Chemical Vapor Deposition AIXTRON TRICENT® cluster tool. Most emphasis was placed on the growth kinetics in the low temperature regime of 450–600 °C which is characterized by surface limited reactions. A low growth activation energy of 0.667 eV was achieved by using Si2H6 and Ge2H6 precursors. Fully strained SiGe layers with Ge contents up to 53% at a record thickness of 29 nm were grown at a very low growth temperature of 450 °C. The dopant incorporation in Si strongly increases with the B2H6 flux but saturates rapidly with increasing PH3 flow. High dopant concentrations of 1.1 × 1020 cm−3 and 1 × 1021 cm−3 were obtained for Si:P and Si:B doping, respectively, at a growth temperature of 600 °C. For Si0.56Ge0.44 layers the maximum dopant concentrations achieved were 5 × 1020 cm−3 for P at 500 °C and 4 × 1020 cm−3 for B doping at 600 °C.

► Pseudomorphic SiGe growth at low temperature (450–600 °C).
► Fully strained SiGe layers with Ge concentrations up to 53%.
► Highly B and P doped Si and SiGe layers are synthesized.
► One order of magnitude higher B doping is possible in Si as compared to P doping.