Development of crystallographic process technology for piezoelectric actuator for bio-mems device

Abstract

Recently, the lead free piezoelectric material, which could be used for the actuator and the sensor of medical care devices, such as the health monitoring system (HMS) and the drug delivery system (DDS), is strongly required. In this study, we try to find a new biocompatible and lead-free piezoelectric material, by using the three-scale processcrystallographic analyses scheme, which consists of the first-principles calculations, the homogenization based finite element method, and the process optimization algorithm. After numerical calculations, we found an optimum biocompatible element combination and a tetragonal crystal structure of candidate material MgSiO3. As a result of process crystallography simulation to adjust with the selected substrate Au(111), lattice parameters of MgSiO3 with tetragonal structure were obtained as a=b=0.3449nm and c=0.3538nm, and its aspect ratio was 1.026. The piezoelectric stress constants of a non constraint MgSiO3 crystal, e33=4.57C/m2, e31=-2.20C/m2 and e15=12.77C/m2, were obtained. Macro homogenized piezoelectric stress constants of MgSiO3 thin film were obtained as e33=5.10C/m2, e31=-3.65C/m2 and e15=3.24C/m2. We confirmed the availability of our process crystallographic simulation scheme for a new biocompatible piezoelectric material design through the comparison with the experimental observation of a newly generated MgSiO3 thin film material.