Initial Stages of Growth of Barium Zirconate Titanate and Barium Stannate Titanate Films on Single-Crystal Sapphire and Silicon Carbide

Resumo

The initial stages of growth of barium zirconate titanate and barium stannate titanate ferroelectric films on single-crystal sapphire and silicon carbide are studied for the first time. The choice of substrates is dictated by the possibility of using such structures in ultra-high frequency devices. The growth of discontinuous BaZr_xTi_1–xO₃ films is found to be mediated by the gas phase mass transport mechanism in the studied temperature range. For deposition of BaSn_xTi_1–xO₃ films, the mechanism of mass transport switches at ~800°C from surface diffusion to gas phase diffusion; also, the films deposited on sapphire and silicon carbide have considerably different elemental composition. The formation of an intermediate SiO₂ layer is noted on silicon carbide during the growth of oxide films on this substrate, its thickness depending on the deposition temperature.