Influences of particle size upon room temperature structure of BaTiO3 thin films on p-Si substrates

Abstract

The current study performed the growth of BaTiO3 thin film on p-Si substrate by using RF-Magnetron sputtering system and the effects of thickness and particle size of the thin film on several structural characteristics of thin film were investigated. Initially, the interrelationship between the thickness and particle size of thin film was elucidated. Based upon the results obtained, the systematic study was made to evaluate the influences of particle size of BaTiO3 thin film on crystal quality, crystal structure, lattice parameter, tetragonality, and stress. In case of BaTiO3 thin film made of specific particle size less than 45 nm as in the current study, the XRD peak at (200) and Raman’s 630 cm−1 band, both typical for cubic BaTiO3, were observed at room temperature. In addition, the lattice parameter was increased and the tetragonality was decreased with the decrease of particle size. It was thus found that the particle size of that range could lead to the formation of cubic crystal structure even at room temperature. It was also shown that the decease of particle size results in the reduction of the stress applied to thin film. It was therefore demonstrated for the first time in this study that one can determine the room temperature crystal structure of BaTiO3 thin film simply by controlling its particle size.