New cost effective ZnO:Al films deposited by large area reactive magnetron sputtering

Al-doped ZnO (ZnO:Al or AZO) films have successfully been fabricated on large area glass substrates by sputtering Zn-Al metallic targets (Al content 1-2 wt%) in an in-line reactive mid-frequency (MF) magnetron sputtering process. A new target technology (CleanMag/spl trade/) based on moving magnets as well as conventional target technology (TwinMag/spl trade/) were utilized. The dependence of microstructure and the obtained optical and electrical properties of the AZO films on deposition parameters, such as working gas pressure, sputtering MF power and substrate temperature, was investigated in detail. Best results showed an extinction coefficient k of less than 2 /spl times/ 10/sup -3/ and a resistivity /spl rho/ below 270 /spl mu//spl Omega/cm. At Fraunhofer IST a fairly good homogeneity of /spl plusmn/6% on an area of 1000 /spl times/ 600 mm/sup 2/ was obtained.