PREPARATION AND CHARACTERIZATION OF THE Au/PZT/BIT/p-Si HETEROSTRUCTURE 

Abstract

The Au/PZT/BIT/p-Si heterostructure was fabricated by pulsed laser deposition technique. The effect of introducing a BIT buffer layer between the PZT films and Si substrate on the crystallinity, the ferroelectric characteristics and the electrical characteristics of the ferroelectric film system, as well as the conductivity behavior of the Au/PZT/BIT/p-Si heterostructure were investigated. The PZT films deposited on p-Si with a BIT buffer layer were found to grow with a preferred orientation along(110) direction. In the case of identical thickness(400?nm) of ferroelectric layer, the PZT/BIT multilayer ferroelectric thin films showed a better ferroelectric property than PZT thin films. The clockwise rotational C-V hysteresis loop of the Au/PZT/BIT/p-Si heterostructure indicated that the PZT/BIT ferroelectric thin films had controlled the Si surface potential and showed a characteristic of polarization-type switching. The current-voltage (I-V) curves showed that the heterostructure was conductive only in the one voltage direction and the leakage currents are too low to identify in the opposite direction. The conduction in low voltage region displays an ohmic behavior and the current transportation in ferroelectric thin films at the high voltage region is ascribed to the space-charge limited current. The remnant polarization of the PZT/BIT films system remained tobe 90% of the initial value after 109 bipolar switching cycles.