Pulsed DC magnetron sputtering of transparent conductive oxide layers
A comprehensive material study of different transparent conductive oxides (TCOs) is presented. The layers are deposited by pulsed direct current (DC) magnetron sputtering in an inline sputtering system. Indium tin oxide (ITO) films are studied in detail. The optimum pressure of 0.33 Pa (15Ar:2O2) produces a 300-nm thin film with a specific resistivity rho of 2.2×10-6 ohm m and a visual transmittance of 81%. Alternatively, ZnO:Al and ZnO:Ga layers with thicknesses of 200 and 250 nm are deposited with a minimum resistivity of 5.5×10-6 and 6.8×10-6 ohm m, respectively. To compare the optical properties in the ultraviolet (UV) range, the optical spectra are modeled and the band gap is determined.