The composition dependence of the rf-magnetron sputtered La-Ni-O films

La-Ni-O thin films of different La and Ni concentration ratios were deposited on the (111)Si at a substrate temperature of 260℃ by a rf-magnetron sputtering system with a combined target. Results shows that the film is of amorphous structure when La content was too high. The film was with (100) preferred orientation and metallic electric conduction as the atomic concentration ratio of La to Ni was less than 1.44∶1. When the composition gets the stoichiometric composition (Ni∶La=1:1), the lattice constant and the sheet resistivity of the film reaches their minimums as 0.389nm and 6.4Ω·μm respectively. Then, as excessiveness of Ni increases, NiO phase appears and LaNiO_3(110) orientation is observed. The results also demonstrated that the excessiveness of Ni affected the conductivity more than that of La at the same lattice constant. A practicable explanation also was provided according to the conducting mechanism of LaNiO_3.