Selective epitaxial growth of Si _1-xGe _x films via the alternating gas supply of Si ₂H ₆, GeH ₄, and Cl ₂: Effects of Cl ₂ exposure

Si _1-xGe _x films were epitaxially grown on Si(0 0 1) substrates at various ratios of flow rates of Si ₂H ₆ and GeH ₄. Si _1-xGe _x films were also selectively grown on Si windows through modified alternating gas supply manner, repeating the unit cycle which consists of the Si _1-xGe _x growth step and Cl ₂ exposure step. Injection of Cl ₂ enhanced the selectivity of the selective growth of Si _1-xGe _x by etching away the spurious nuclei or deposits formed on oxide area. The separate addition of Cl ₂ resulted in decrease of the growth rate and Ge concentration of Si _1-xGe _x film. Meanwhile, Ge concentration in Si _1-xGe _x films was insignificantly affected by the variation of the flow rates and exposure durations of Cl ₂.