Selective epitaxial growth of Si1-xGex films via the alternating gas supply of Si2H6, GeH4, and Cl-2: Effects of Cl-2 exposure

Abstract

Si1-xGex films were epitaxially grown on Si(001) substrates at various ratios of flow rates of Si2H6 and GeH4. Si1-xGex films were also selectively grown on Si windows through modified alternating gas supply manner, repeating the unit cycle which consists of the Si1-xGex growth step and Cl-2 exposure step. Injection of Cl-2 enhanced the selectivity of the selective growth of Si1-xGex 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 Si1-xGex film. Meanwhile, Ge concentration in Si1-xGex films was insignificantly affected by the variation of the flow rates and exposure durations of Cl-2. (C) 2012 Elsevier B.V. All rights reserved.