Three-scale analysis of BaTiO3 piezoelectric thin films fabrication process and its experimental validation

A three-scale analysis of crystal growth process is newly proposed based on the first-principles calculation and on the finite element analysis in order to generate a new biocompatible piezoelectric thin film. Crystal growth process of lead-free BaTiO3 thin films was designed and experimentally generated on SrTiO3(100), (110), (111), and MgO(100) substrates using the radio-frequency magnetron sputtering method. Crystal structures of BaTiO3 were measured by X-ray diffraction (XRD) theta/2 theta scan. We used Pt for the electrode and measured piezoelectric strain constants d (33) using the ferroelectric measurement system. As a result, analytical crystal orientation fractions on SrTiO3(110) and (111) substrates had good quantitative agreement with experimental ones, and ones on SrTiO3(100) and MgO(100) substrates corresponded with these experimental crystal structures. Furthermore, analytically determined piezoelectric strain constants d (33) qualitatively showed a good agreement with experimental ones. Especially, for SrTiO3(100) and MgO(100) substrates, the differences of d (33) depending on orientation fractions were analyzed by the three-scale simulation accurately. Consequently, it is confirmed that the three-scale analysis is a useful simulation tool to design new biocompatible piezoelectric thin films.