Highly conductive and transparent ZnO:Al thin films prepared on high-temperature substrates by d.c. magnetron sputtering

Highly conductive and transparent aluminium-doped ZnO (AZO) thin films have been prepared on high-temperature substrates using d.c. magnetron sputtering. In AZO films, the spatial distribution of resistivity across substrates placed parallel to the target was improved by deposition at substrate temperatures above 300 °C. AZO films with resistivities of 2?5 x 10^?4 Ω cm were prepared under sputter gas pressures of between 0.6 and 3.0 Pa and at a substrate temperature of 350 °C. In addition, milky AZO films with a textured surface were prepared on high-temperature substrates under sputtering conditions which suppressed the c-axis orientation. A total transmittance of 72% and a haze factor of 63% at a wavelength of 500 nm and a sheet resistance as low as 2.0 Ω sq^?1 were obtained in milky AZO films 3 μm thick prepared at a sputter gas pressure of 12 Pa and a substrate temperature of 350 °C.