Fabrication of low-resistance LaNi_xO_(3+δ) thin films for ferroelectric device electrodes

LaNiO_3 thin films with different La/Ni ratios were deposited on Si substrates by sol-gel process. The electrical resistivities of LaNi_xO_(3+δ) films with different La/Ni ratios were measured by four-probe method.LaNi_(0.95)O_(3+δ) thin film has the lowest resistivity. First-principle calculations show that LaNi_(0.95)O_(3+δ) has the largest Ni-O-Ni bond angle and the shortest Ni-O bond length, which means LaNi_(0.95)O_(3+δ) has the strongest metallic property, hence, the electrical resistivity is the lowest. Au/PZT(PbZr_(0.52)Ti_(0.48)O_3)/LaNi_xO_(3+δ) and Au/PZT/Pt ferroelectric capacitors were fabricated to evaluate LaNi_xO_(3+δ) as a bottom electrode. It is shown that fatigue properties of PZT films can be significantly improved by using LaNi_xO_(3+δ) instead of Pt as the bottom electrode. The Ⅰ-Ⅴ test results of PZT films show that LaNi_(0.95)O_(3+δ) as bottom electrode can reduce the threshold voltages of PZT films, suggesting that La/Ni ratio in LaNi_xO_(3+δ)has a large influence on the film properties.

Fabrication of low-resistance LaNixO3+δ thin films for ferroelectric device electrodes

LaNiO₃ thin films with different La/Ni ratios were deposited on Si substrates by sol-gel process. The electrical resistivities of LaNi_xO_3+δ films with different La/Ni ratios were measured by four-probe method. LaNi_0.95O_3+δ thin film has the lowest resistivity. First-principle calculations show that LaNi_0.95O_3+δ has the largest Ni–O–Ni bond angle and the shortest Ni–O bond length, which means LaNi_0.95O_3+δ has the strongest metallic property, hence, the electrical resistivity is the lowest. Au/PZT (PbZr_0.52Ti_0.48O₃)/LaNi_xO_3+δ and Au/PZT/Pt ferroelectric capacitors were fabricated to evaluate LaNi_xO_3+δ as a bottom electrode. It is shown that fatigue properties of PZT films can be significantly improved by using LaNi_xO_3+δ instead of Pt as the bottom electrode. The I-V test results of PZT films show that LaNi_0.95O_3+δ as bottom electrode can reduce the threshold voltages of PZT films, suggesting that La/Ni ratio in LaNi_xO_3+δ has a large influence on the film properties.