Study On PZT Thin Film Deposited Via Magnetron Sputtering Method

Because of good electromechanical coupling characteristics, large remnant polarization, piezoelectric coefficient, pyroelectric coefficient, excellent dielectric properties, low leakage current density and could be integrated with MEMS technology, PZT (lead zirconate titanate) thin film was widely applied in various fields of microelectronics, such as ferroelectric memory, digital switches, vibration energy harvesting, fuel cell, etc..In this paper, PZT thin films were deposited via radio-frequency magnetron sputtering method onto Pt/Ti/SiO2/Si substrate at different temperature for different time, had different thickness consequently. Then, they were annealed at500℃,600℃and700℃with rapid thermal annealing process. Principle and the preparation process of PZT thin films through the sol-gel method were introduced. To determine the subsequent thermal annealing process parameters, the PZT precursor solution was tested by differential thermal analysis(DTA). PZT thin films with different thickness was produced and annealed with rapid thermal annealing process. Surface morphology, X-ray diffraction (XRD) analysis, residual stress, dielectric and leakage characteristic of the PZT thin film prepared via the two deposition method were tested and analyzed.The results show that, average grain size of PZT thin film via RF magnetron sputtering is in the40-90nm range, the annealing temperature can effectively make the film average roughness reduced from2.72nm to0.316nm, a sputtering temperature rise causes greater volatility of the grain size from89.53nm reduced to44.01nm; average residual stress of PZT thin films prepared by RF magnetron sputtering changes relative greater, but its surface is more uniform, more effective control by temperature changes. The ones via sol-gel method are more stable and change within lGPa; Dielectric constant of PZT thin films prepared by RF magnetron sputtering can be35,000which larger than ones prepared by the sol-gel method about10times. But as the XRD analysis, it is not the dielectric constant of PZT with stability; when testing DC electric field strength set491.8KV/cm, leakage current density of the RF magnetron sputtering PZT thin film is only1.75X10-9A/cm2, and it can withstand the DC electric field strength exceeds983.55KV/cm, the linear increase coefficient of leakage current density is1.79×10-12after polynomial fitting. As test field strength set approximately100KV/cm, a minimum leakage current density of the ones prepared by sol-gel method is 1.37×10-6A/cm2and the linear growth coefficient is1.52×10-8which are much larger than the one of magnetron sputtering PZT thin film.