Growth kinetics of amorphous interlayers by solid-state diffusion in ultrahigh-vacuum-deposited polycrystalline V thin films on (001)Si

Abstract

The growth kinetics of an amorphous interlayer (a-interlayer) formed by solid-state diffusion in ultrahigh-vacuum-deposited polycrystalline V thin films on (001)Si have been investigated by conventional and high-resolution transmission electron microscopy. The growth was found to follow a linear growth law initially in samples annealed at 430–465 °C. The growth then slows down and deviates from a linear growth law as a critical thickness of the a-interlayer is reached. The activation energy of the linear growth and maximum thickness of the a-interlayer were measured to be 1.1±0.3 eV and 4.5 nm, respectively. The correlations among differences in atomic size and electronegativity between metal and Si atoms and activation energy of the linear growth, critical and maximum a-interlayer thickness, the calculated free-energy difference in forming the amorphous phase, as well as atomic mobility in Ti/Si, Zr/Si, Hf/Si, Ta/Si, Nb/Si, and V/Si systems are discussed.