Selective epitaxial growth of Si1−xGex films via the alternating gas supply of Si2H6, GeH4, and Cl2: Effects of Cl2 exposure

Si1−xGex films were epitaxially grown on Si(0 0 1) 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 Cl2 exposure step. Injection of Cl2 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 Cl2 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 Cl2.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Selective epitaxial growth of S1−xGex on Si windows. ► Si1−xGex film by consecutively repeating Si1−xGex growth and Cl2 exposure. ► Separate addition of Cl2: decrease of growth rate and Ge concentration. ► Increase in exposure of Cl2: insignificant effects on the Ge concentration.