Films of lead lanthanum titanate (PLT) are deposited on n-type (100) Si and Pt/TiO2/Ti/SiO2/(100)Si substrates by using ultrasonic nebulized spray deposition. In this work, Pb(CH3COO)(2). 3H(2)O, La(NO3)(3). 6H(2)O, Ti(i-C3H7O)(4) are used as reactants. Experimental results reveal that the films are transformed from tetragonal to nearly cubic as the lanthanum content increases. The refractive index and grain size decrease with the increase of La content in the films. From C-V and I-V measurements of the Al/PLT/n-Si (MIS) and Pt/PLT/Pt/TiO2/Ti/SiO2/n-Si (MIM) structures, the dielectric properties are determined. The permittivities are found to increase with the La content to a maximum value of about 275 and 530 for the MIS and MIM structures, respectively, and then decrease with further increase of La content for the films grown at 550 degrees C. The results of I-L! measurements indicate that the leakage currents of the MIS structure are higher than in the MIM structure. The P-E hysteresis loop became slimmer with the increase of La concentration due to lower tetragonality (c/a), and when the La content is higher than 20 mol%, the films behave like a normal dielectric.