| 초록 |
With development of electrical industry, demand for a ceramic based capacitor with high energy storage density has been increased gradually. Many researchers have been studied to obtain high energy density, decreasing the film thickness through Sol-gel method, spin coating and so on. However, thin films are vulnerable to high voltage required to applications. Nanograined lead-free 6Bi0.5Na0.5TiO3(BNT)-4Sr0.7Bi0.2TiO3(SBT) thick films were deposited on substrate using an aerosol deposition (AD) method. The AD method based on particle's physical collision can fabricate dense film on substrate at room temperature without additional sintering process which is usually required to ceramic materials. Even though, the AD method has many advantages, there is a critical issue which is generated residual stress between the ceramic film and substrate. Annealing process is inevitable to release residual stress. This annealing process, however, induce exfoliation when the coefficient of thermal expansion (CTE) between the film and substrate is different. To solve this issue, shape memory alloy (SMA) substrate is introduced. As a result, the dielectric properties of the AD films are improved by reducing residual stress. This study suggests residual stress relaxation of AD film through SMA substrate could improve the dielectric performance. |
