Improved structural and electrical properties of thin ZnO:Al films by dc filtered cathodic arc deposition

Transparent conducting oxide films are usually several 100-nm thick to achieve the required low sheet resistance. In this study, we show that the filtered cathodic arc technique produces high-quality low-cost ZnO:Al material for comparably smaller thicknesses than achieved by magnetron sputtering, making arc deposition a promising choice for applications requiring films less than 100-nm thick. A mean surface roughness less than 1 nm is observed for ZnO:Al films less than 100-nm thick, and 35-nm-thick ZnO:Al films exhibit Hall mobility of 28 cm²/Vs and a low resistivity of 6.5 × 10⁻⁴ Ωcm. Resistivity as low as 5.2 × 10⁻⁴ Ωcm and mobility as high as 43.5 cm²/Vs are obtained for 135-nm films.