High-rate reactive high-power impulse magnetron sputtering of transparent conductive Al-doped ZnO thin films prepared at ambient temperature

Reactive high-power impulse magnetron sputtering was used for high-rate (deposition rate of 60 nm/min) deposition of conductive (resistivity of 3 x 10(-3) Omega cm) and optically transparent (extinction coefficient at the wavelength of 550 nm of 0.01) ZnO:Al thin films at ambient temperature (< 40 degrees C). We used planar Zn:Al target (3.09 at.% of Al) with diameter of 100 mm and thickness of 6 mm mounted on strongly unbalanced magnetron. The films were deposited in argon-oxygen atmosphere at constant argon and oxygen partial pressure of 2.0 Pa and 0.1 Pa, respectively. An average target power and voltage pulse length were kept constant to 1.9 Wcm(-2) and 200 mu s, respectively. A pulse-averaged target power density was varied in the range of 190 Wcm(-2)-940 Wcm(-2). Optical emission spectroscopy was used for better understanding of correlations between plasma discharge properties and structural, electrical and optical properties of prepared films.