Crystal Growth Prediction by First-Principles Calculations for Epitaxial Piezoelectric Thin Films

Abstract

A numerical prediction scheme of crystal growth on various substrates by using the first-principles calculation was proposed to analyze the epitaxial processes of the piezoelectric thin films, such as the sputtering, the chemical vapor deposition and the molecular beam epitaxy processes. At first, we analyze the epitaxial strain of crystal cluster in piezoelectric thin film, which is caused by the lattice mismatch with the substrate. When the epitaxial strain is introduced in the unit cell of the crystal cluster, the total energy can be calculated by employing the pseudo-potential method based on the density functional theory. Then, a preferred orientation of crystal cluster is selected from the crystal conformations on the substrate which satisfy the structural stability condition. This numerical scheme was applied to BaTiO 3 thin films processes fabricated on various substrates, such as SrTiO 3 (110), SrTiO 3 (001), MgO(100) and LaTiO 3 (001). Numerical results show that our process crystallographic design scheme, which employs the total energy increment of cluster, is efficient tool to evaluate the possibility of thin film crystal growth. Finally, it was confirmed that numerical results of preferred orientations have good correspondence with experimental ones.

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

“…Figure 1 shows a flow chart of the analysis algorithm. The specific analysis procedure has been reported previously [8][9][10][11]; therefore, only a summary is presented in this article.…”

“…We calculate the microstructure consisted of inhomogeneous crystal grains using the process crystallography simulation [8]. Figure 3 shows two examples of analytical results of BaTiO 3 crystal clusters on SrTiO 3 (100) substrate, which have (a) [001] and (b) [100] orientations.…”

“…In order to fabricate a new biocompatible piezoelectric thin film, a three-scale analysis was proposed based on the first-principles calculation [8]. The preferred orientations and dielectric properties of piezoelectric thin films were compared with experimental results reported in Ref.…”

Development of a New Biocompatible MgSiO3 Piezoelectric Thin Film

“…In the previous study, new biocompatible materials were found by using the first-principles calculation, and the MgSiO 3 with the perovskite tetragonal structure, which was constructed by biocompatible elements and had the piezoelectric property, was found as the best candidate material (13) (14) .…”