(Na0.5K0.5)NbO3(NKN) lead free thin films were synthesized by means of an acetic acid based sol-gel process on Pt/Ti/SiO2 /Si substrates. Na-acetate, K-acetate and Nb-pentaethoxide were used as metal precursors and acetic acid as the solvent. The effect of different calcination temperatures on the properties of the NKN films was investigated by X-ray diffraction, scanning electron microscopy, leakage current and hysteresis measurements. Low calcination temperatures led to low currents at high electric fields whereas high calcination temperatures led to low currents at low electric fields. Based on these findings calcination at low temperature was combined with a post annealing treatment. Low leakage currents of 4×10-4 A/cm2 at 150 kV/cm and 2Pr and 2Ec values of 28 μC/cm2 and 150 kV/cm, respectively, could be obtained. All films were single phase NKN with random crystal orientations and no crack or pore formation was visible on the surface. (Na0.5K0.5) NbO3 (NKN) lead free thin films were synthesized by means of an acetic acid based sol-gel process on Pt / Ti / SiO2 / Si substrates. Na-acetate, K-acetate and Nb-pentaethoxide were used as metal precursors and acetic acid as the solvent. The effect of different calcination temperatures on the properties of the NKN films was investigated by X-ray diffraction, scanning electron microscopy, leakage current and hysteresis measurements. Low calcination temperatures led to low currents at high electric fields whereas high calcination temperatures led to low currents at low electric fields. Based on these findings calcination at low temperature was combined with a post annealing treatment. Low leakage currents of 4 × 10-4 A / cm 2 at 150 kV / cm and 2Pr and 2Ec values ​​of 28 μC / cm2 and 150 kV / cm, respectively, were obtained. All films were single phase NKN with random crystal orientations and no crack or pore formation was visible on the surface.