Process-property correlations of excimer laser ablated bismuth titanate films on silicon

Abstract

Bismuth titanate thin films were deposited by the excimer laser ablation technique directly onto bare silicon substrates, SiO₂ and Si₃N₄ coated silicon. The impact of process parameters such as gas pressure, laser fluence, processing temperature, and the presence of an oxygen plasma were studied with regards to the ferroelectric-semiconductor interface. The density of interfacial surface state (Nss) at the flatband voltage was found to be on the order of 10¹²-10¹⁴ eV^-1cm^-2. Hysteretic capacitance-voltage data indicated charge injection from the substrate was the dominant mechanism, masking any polarization mode. Films deposited on SiO₂ coated silicon did, however, exhibit polarization type switching.