Dynamics of SrTiO3 surface during wet etching and high-temperature annealing

Abstract

We have studied the dynamics of SrTiO3(001) surface etching and annealing in order to prepare the best possible surface for thin film deposition. Wet etching in pH-controlled NH4F-HF was used to obtain an atomically flat surface which was terminated by the TiO2 layer, as shown by ion scattering measurements. Annealing of the surface at up to 800°C was needed to stabilize the etched surface and to obtain straight step edges. The preferential TiO2 termination was preserved even after annealing. High-temperature scanning tunneling microscopy was used to determine the optimal annealing conditions and to gain an understanding of the surface migration process, which is essential for the understanding of the film growth process on SrTiO3 substrates at various temperatures.