Dielectric characteristics investigation of (Ba_0.7Sr_0.3)(Ti_0.9Zr_0.1)O₃ ferroelectric thin films

abstract

By the radio frequency (RF) magnetron sputtering methods, (Ba_0.7Sr_0.3)(Ti_0.9Zr_0.1)O₃ (BSTZ) ferroelectric thin films were deposited on the Pt/Ti/SiO₂/Si(100) substrates. The crystal structural and microstructure of these thin films were analyzed by means of the XRD, SEM, and AFM. Moreover, the dielectric characteristics were also investigated by the C-V and J-E analyses. The optimal deposition parameters for these BSTZ thin films were: RF power is 160 W, oxygen concentration is 25%, substrate temperature is 580°C, and chamber pressure is 0.075 mPa. Under these optimal deposition conditions, the (111) and (110) oriented polycrystalline of the BSTZ thin films grow easily. And under a bias voltage of 0.5 MV/cm, the dielectric constant and leakage current density of the BSTZ thin films are 191 and 3×10⁻⁸ A/cm², respectively. In addition, under various measured temperatures (0 ∼ 80°C) and frequencies (100 kHz ∼ 1 MHz), all the dielectric constants remain almost unchanged. Compared to BSTZ thin films reported previously, in this study, the deposited thin films have the advantage of lower leakage current and hence are suitable for the applications of dynamic random access memory.

KEYWORDS:

• BSTZ
• ferroelectric thin films
• C-V, J-E
• rf sputtering

Funding

We acknowledge the financial support of the National Science Council of the Republic of China (NSC 102-2633-E-272-003).