Synthesis and characterisations of sol–gel–derived LaNiO3 thin–film electrodes on Si substrates

We present the fabrication and characterisation of conductive LaNiO3 (LNO) thin films, deposited on different substrates including Si(100), SiO2/Si(100) and Pt/Ti/SiO2/Si(100) by the sol-gel spin-coating technique. Deposition parameters, such as the sol concentration and annealing temperature as well as the number of coating layers, were optimised to obtain the desired film quality. X-ray diffraction analysis showed that crystalline and highly (110) oriented LNO thin films were obtained after annealing at 750 degrees C. Scanning electron microscopy images revealed that LNO films show a dense and smooth surface. Moreover, the crystallites' size increased with increasing film thickness, which resulted in the enhancement of electrical conductivity. The well-controlled crystallinity and low resistivity of 3.73 x 10(-4) Omega.cm, measured on a film thickness of 200 nm, indicate that LNO thin films can be used as the template and electrode for the fabrication of integrated piezoelectric thin-films on Si substrates.