Effects of deposition temperature and post-annealing on structure and electrical properties in (La0.5Sr0.5)CoO3 films grown on silicon substrate

(La0.5Sr0.5)CoO3 (LSCO) thin films have been fabricated on silicon substrate by the pulsed laser deposition method. The effects of substrate temperature and post-annealing condition on the structural and electrical properties are investigated. The samples grown above 650A degrees C are fully crystalline with perovskite structure. The film deposited at 700A degrees C has columnar growth with electrical resistivity of about 1.99x10(-3) Omega cm. The amorphous films grown at 500A degrees C were post-annealed at different conditions. The sample post-annealed at 700A degrees C and 10(-4) Pa has similar microstructure with the sample in situ grown at 700A degrees C and 25 Pa. However, the electrical resistivity of the post-annealed sample is one magnitude higher than that of the in situ grown sample because of the effect of oxygen vacancy. The temperature dependence of resistivity exhibits semiconductor-like character. It was found that post-annealing by rapid thermal process will result in film cracks due to the thermal stress. The results are referential for the applications of LSCO in microelectronic devices.