Selective epitaxial growth of stepwise SiGe:B at the recessed sources and drains: A growth kinetics and strain distribution study

The selective epitaxial growth of Si_1-xGe_x and the related strain properties were studied. Epitaxial Si_1-xGe_x films were deposited on (100) and (110) orientation wafers and on patterned Si wafers with recessed source and drain structures via ultrahigh vacuum chemical vapor deposition using different growing steps and Ge concentrations. The stepwise process was split into more than 6 growing steps that ranged in thicknesses from a few to 120 nm in order to cover the wide stages of epitaxial growth. The growth rates of SiGe on the plane and patterned wafers were examined and a dependence on the surface orientation was identified. As the germanium concentration increased, defects were generated with thinner Si_1-xGe_x growth. The defect generation was the result of the strain evolution which was examined for channel regions with a Si_1-xGe_x source/drain (S/D) structure.