Kinetic instability in the growth of CaF2 on Si(111)

Even when thermodynamic driving forces favor a thin film to grow with a particular growth mode, this preferred growth mode may be kinetically inaccessible. While this is not uncommon at low temperature (short diffusion length), we show that in the Si(111)/CaF2 system, during the early stage of growth, the preferred growth mode may be inacessible at temperatures as high as 660°C, where the surface diffusion length (several microns) exceeds the terrace spacing. Once the preferred growth mode is initiated the surface morphology becomes unstable, leading to a fast and striking change in layer occupancies. © 1994 The American Physical Society.