Dielectric properties of electron beam evaporated indium oxide thin films

Indium oxide thin films have been deposited in vacuum (10-5 Torr) by thermal evaporation of In2O3 powder using electron beam gun. X-ray diffraction studies of both the unannealed and annealed films indicate that the indium oxide films thus deposited are amorphous in structure. Pure aluminium has been deposited as electrodes to form the sandwich structure of aluminium-indium oxide-aluminium. With this structure, the variations of capacitance and dielectric loss (tan delta) of the indium oxide films have been studied in the frequency range 200 Hz-30 kHz, before and after annealing at 473K for 2 hours. The annealing study reveals a corresponding decrease in both the capacitance and tan delta with frequency. From capacitance and area measurements the dielectric constant of the film has been evaluated. The variation of tan delta with frequency has been characterised by the loss peaks. The changes of capacitance and tan delta with frequency at different temperatures (300 K - 525 K) and their dependence on temperature at different frequencies have also been studied and the results are discussed. (author)