Investigation of Electrical Properties and Structure of ITO Thin Films Fabricated by Magnetron Sputtering

In this paper, electrical properties of thin ITO films formed by magnetron sputtering on Si, sapphire, Si3N4 on Si substrates, as well as on polyvinylidene fluoride and a glass slide, depending on the deposition process parameters were investigated. A characteristic power-law dependence of the sheet resistance on the film thickness was obtained in the thickness range from 20 to 100 nm. Process modes were determined that provide the lowest sheet resistance values from 98 to 155 Ohm/sq. for 100 nm thick films during formation without heating the substrate and direct current sputtering at a magnetron power of 80 to 85 W. It was revealed that sputtering in a pulsed mode at a pulse frequency of 10 to 100 kHz and a pulse duty cycle of 15 to 80% leads to an increase in the sheet resistance of the films in the range under study. Heating the substrate holder to 200°C during formation leads to an increase in the degree of crystallinity of the film and a decrease in the sheet resistance to 71 Ohm/sq. and 77 Ohm/sq. for ITO on Si and sapphire substrates, respectively. On polyvinylidene fluoride substrates, the highest transmittance of the ITO film is 86% at a wavelength of 550 nm.