Investigation of PbZr0.4Ti0.6O3 capacitors with room temperature as-grown LaNiO3 electrodes
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LaNiO3 (LNO) film grown at room temperature (RT) by RF magnetron sputtering is used as the electrode for integrating LaNiO3/PbZr0.4Ti0.6O3/LaNiO3 (LNO/PZT/LNO) capacitor on SrTiO3 (STO) substrate. For comparison, LNO film grown at 250 °C is also used as the electrode of PZT capacitor. Reflection high energy electron diffraction (RHEED) technique is used to characterize the LNO film, it is found that LNO film prepared at 250 °C is epitaxial although no diffraction pattern is found for RT as-grown LNO. Ferroelectric properties of PZT films strongly depend on the LNO bottom electrodes. The remanent polarization (Pr) and coercive voltage (Vc), measured at 5 V, for the capacitors with LNO bottom electrodes prepared at RT and 250 °C, are 20 and 37 μC/cm2, 1.67 and 1.95 V, respectively. No obvious degradation of polarization for PZT capacitors with RT as-grown LNO electrodes can be found. Room temperature as-grown LNO as both bottom and top electrodes to fabricate ferroelectric capacitors can save 2/3 thermal budgets, which may pay a way to decrease the potential challenges of devices resulting from the oxidation, interdiffusion or reactions during integrating ferroelectric capacitors with Si technologies.
KeywordsIrO2 Reflection High Energy Electron Diffraction Switchable Polarization Oxide Electrode LaNiO3
This work is partly supported by the NSFC (No. 50572021), SRF for ROCS from both State Education Ministry and Ministry of Personnel, the NSF of Hebei Province of China (No. E2005000130), and Foundations of Hebei Provincial scientific/educational departments (No. 04213579 and No. 2005213), and Hebei University.