Electrical Properties of a 0.95(Na0.5K0.5) NbO3-0.05CaTiO(3) Thin Film Grown on a Pt/Ti/SiO2/Si Substrate

Abstract

An amorphous phase was formed in a 0.95(Na0.5K0.5)NbO3-0.05CaTiO(3) (NKN-CT) film grown at 300 degrees C, and a low-temperature transient Ca2Nb2O7 phase was formed in the film grown at 500 degrees C. In films grown at high temperatures (600 degrees C), secondary phases such as K5.75Nb10.85O30 and K4Ti10Nb2O27 were developed without the formation of a NKN-CT phase, probably because of Na2O evaporation. The same secondary phases were formed in the film grown at 300 degrees C and subsequently annealed at 850 degrees C under an air atmosphere. However, a homogeneous NKN-CT phase was formed in films grown at 300 degrees C and subsequently annealed at 830 degrees C-880 degrees C under the K2O and Na2O atmospheres. Moreover, the film annealed at 830 degrees C in particular exhibited good electric and piezoelectric properties, including a high dielectric constant of 747 with a low dissipation factor of 0.93% at 100kHz, low leakage current density of 2.0x10(-7)A/cm(2) at 0.1MV/cm, and high P-r and d(33) values of 15.4C/cm(2) and 124pm/V at 100kV/cm, respectively.