( )0.5Pb(Ni1/3Nb2/3)O-3-0.35PbTiO(3)-0.15PbZrO(3) (PNNZT) thin films fabricated on Pt/Ti/SiO2/Si(100) substrate using pulsed laser deposition (PLD) technique is discussed in this work. The effect of substrate temperature (T-s) on phase formation, microstructure, dielectric and ferroelectric properties of PNNZT thin films have been studied by varying the T-s from 100 to 800 degrees C with an interval of 100 degrees C. A minimum T-s of similar to 500 degrees C was required to obtain the pure perovskite phase while the best electrical properties are achieved at T-s = 800 degrees C. The relative permittivity (epsilon(r)')) and remnant polarization (P-r) of the PNNZT thin films increased from 130 to 1510 and 13.7 to 18.5 mu C/cm(2) (at 1 kHz), respectively with increasing T-s from 500 to 800 degrees C, while the average grain size (GS) grew from 6 to 85 nm. The conductivity and impedance studies led to the understanding of electrical behavior of the deposited PNNZT thin films. The observed changes in electrical properties were ascribed to the grain growth with the increase in T-s.