Influence of LaNiO3 bottom electrode on the structural and physical properties of ferroelectric capacitors

Techniques such as high energy electron diffraction (RHEED), atomic force microscope (AFM) are used to characterize LNO film prepared by rf sputtering. It is found that LNO films are epitaxially grown on the SrTiO₃ (STO) substrates. Root mean square roughness (RMS) of LNO film increases with increasing growth temperature, and then becomes somewhat saturated when deposition temperature is higher than 350 °C. Meanwhile, resistivity of LNO film decreases with increasing growth temperature, and becomes relatively stable when deposition temperature is higher than 200 °C. It is found that ferroelectric properties of LaNiO₃/Pb(Zr,Ti)O₃/LaNiO₃ (LNO/PZT/LNO) capacitors prepared on STO substrate strongly depend on the deposition temperature of LNO bottom electrode. The higher the deposition temperature of LNO bottom electrode, the larger is the switchable polarization of LNO/PZT/LNO capacitor.