Investigation of room temperature electrical resistivities of LaNiO _3-δ thin films deposited by rf magnetron sputtering and high oxygen-pressure processing

Highly (100)-oriented electrically conductive LaNi O3-δ (LNO) thin film with perovskite-type structure was deposited on Si(100) substrates by rf magnetron sputtering at substrate temperatures of 200, 300, 450, and 600 °C with a series of 0%, 20%, 40%, and 60% oxygen partial pressures, respectively. The room temperature (RT) resistivity of LNO films decreases with decreasing substrate temperature at a fixed oxygen partial pressure and with increasing oxygen partial pressure at a fixed substrate temperature. The lowest RT resistivity of as-sputtered LNO thin films was about 5.3× 10-4 cm. This value could be as low as ∼1.55× 10-4 cm by postprocessing called high oxygen-pressure processing at 8 MPa and is comparable to the lowest one, 1.5× 10-4 cm, of epitaxial LNO thin film deposited on lattice-matched SrTi O3, LaAl O3, or sapphire single-crystal substrates.