Multi-layered unit including electrode and dielectric layer

摘要

A multi-layered unit according to the present invention includes a support substrate formed of fused quartz, an electrode layer formed on the support substrate and formed of a conductive material, a buffer layer formed on the electrode layer and formed of a dielectric material containing a bismuth layer structured compound having a composition represented by Bi₄Ti₃O₁₂ and having an excellent orientation characteristic so that the bismuth layer structured compound is oriented in the c axis direction, and a dielectric layer formed on the buffer layer and formed of a dielectric material containing a bismuth layer structured compound having a composition represented by SrBi₄Ti₄O₁₅ and having an excellent orientation characteristic so that the bismuth layer structured compound is oriented in the c axis direction. Since the thus constituted multi-layered unit includes the dielectric layer containing the bismuth layer structured compound oriented in the c axis direction, in the case of, for example, providing an upper electrode on the dielectric layer to form a thin film capacitor and applying a voltage between the electrode layer and the upper electrode, the direction of the electric field substantially coincides with the c axis of the bismuth layer structured compound contained in the dielectric layer. As a result, since the ferroelectric property of the bismuth layer structured compound contained in the dielectric layer can be suppressed and the paraelectric property thereof can be fully exhibited, it is possible to fabricate a thin film capacitor having a small size, large capacitance and an excellent dielectric characteristic.