Low-temperature SiGe(C) epitaxial growth by ultraclean hot-wall low-pressure CVD

By ultraclean hot-wall low-pressure CVD using SiH₄ and GeH ₄ gases, epitaxial growth of Si/Si_1-xGe_x/Si heterostructures with atomically flat surfaces and interfaces on Si(100) is achieved. In in-situ doped Si_1-xGe_x epitaxial growth on the (100) surface in a SiH₄-GeH₄-dopant (PH₃, or B₂H₆ or SiH₃CH₃)-H₂ gas mixture, the deposition rate, the Ge fraction and the dopant concentration are explained quantitatively based on the modified Langmuir-type adsorption and reaction scheme, assuming that the reactant gas adsorption/reaction depends on the surface site materials and that the dopant incorporation in the grown film is determined by Henry's law. From the relationship among impurity and carrier concentrations in the grown film and contact resistivity between metal and the grown film, it is suggested that atomically controlled impurity doping is suitable for increasing carrier concentration in the film and lowering contact resistivity. These results open the way to atomically controlled CVD technology for ultralarge-scale integrations.