CONDENSED MATTER THE ELECTRICAL PROPERTIES OF AMORPHOUS THIN FILMS OF Al−In2O3−Al STRUCTURE DEPOSITED BY THERMAL EVAPORATION

A discussion of electrical properties of amorphous thin films of Al−In2O3−Al structure is presented. Particular attention has been given to the question of film thickness, substrate temperature during deposition and post deposition annealing, since these conditions are known to have a profound effect on the structure and electrical properties of the films. The effects of temperature on the V−I characteristics and effects of frequency on conductivity and capacitance of the Al−In2O3−Al structure are also reported. Activation energies for conduction processes are estimated and the results are discussed in terms of hopping model. The conduction at higher temperature is seemingly a contact limited i.e. Schottky type process, so a transition from hoping to free band conduction takes place. The capacitance decreases with the rise of frequency and lowering of temperature. The values of dielectric constants are estimated and the results are discussed in terms of Schottky type of conduction. The increase in conductivity with the increase in temperature during measurement of electrical properties, film thickness, substrate temperature and post deposition annealing is reported and results are discussed in terms of current theory. Key words: electrical conduction mechanisms; carrier density; trapped electrons; indium interstitials; electron donors; oxygen vacancies; lower oxidation state. 1