Effect of Electric Field on Dielectric Properties of SnO 2 Sb 2 O 3 and their Mixed Thin Films

Thin films of various thicknesses in the MIM structure have been prepared from the the powders of SnO 2 , Sb 2 O 3 and (SnO 2 + Sb 2 O 3 ) of high purity by the thermal evaporation technique in a vacuum of 10 −5 Torr. Dielectric properties of SnO 2 , Sb 2 O 3 , and their mixed thin films have been studied with ac and dc electric fields and frequency. Capacitance and loss tangent are almost independent on dc voltage upto 1.0 V for SnO 2 , 10.0 V for Sb 2 O 3 and 2.5 V for mixed films. These capacitors become unstable at 1.0 V for SnO 2 films and 2.5 V for mixed films. For higher film thicknesses the decay in these films starts at higher voltages. Capacitance and loss tangent increases with applied ac voltage in SnO 2 , Sb 2 O 3 , and their mixed films. A comparison of the capacitance values of SnO 2 , Sb 2 O 3 , and their mixed films showed that the capacitance values are less in Sb 2 O 3 as compared to SnO 2 films. In mixed films the capacitance is greater than the constituent films. These studies have shown that Sb 2 O 3 films are found to be more stable compared to SnO 2 and their mixed films for ac and dc voltages. The results thus obtained on SnO 2 , Sb 2 O 3 , and their films are presented and discussed.