Fabrication of low resistance LaNixO3+d thin films for ferroelectric device electrodes
Abstract LaNiO 3 thin films with different La/Ni ratios were deposited on Si substrates by sol gel process. The electrical resistivities of LaNi x O 3+ d films with different La/Ni ratios were measured by four probe method. LaNi 0.95 O 3+ d thin film has the lowest resistivity. First principle calculations show that LaNi 0.95 O 3+ d has the largest Ni O Ni bond angle and the shortest Ni O bond length, which means LaNi 0.95 O 3+ d has the strongest metallic property, hence, the electrical resistivity is the lowest. Au/PZT (PbZr 0.52 Ti 0.48 O 3 /LaNi x O 3+ d and Au/PZT/Pt ferroelectric capacitors were fabricated to evaluate LaNi x O 3+ d as a bottom electrode. It is shown that fatigue properties of PZT films can be significantly improved by using LaNi x O 3+ d instead of Pt as the bottom electrode. The I V test results of PZT films show that LaNi 0.95 O 3+ d as bottom electrode can reduce the threshold voltages of PZT films, suggesting that La/Ni ratio in LaNi x O 3+ d has a large influence on the film properties.