ZnO:Al Films Prepared by Reactive Mid-frequency Magnetron Sputtering with Rotating Cathode

Al-doped zinc oxide (ZnO:Al, AZO) films were deposited on glass substrates using a reactive mid-frequency (MF) magnetron sputtering process with rotating cathodes. The influence of deposition parameters on structural, electrical and optical properties of AZO films is investigated. It is observed that the rotating magnetron targets exhibited a sputtered metallic surface over a wider range, and there is no re-deposition zone between the racetracks. The films deposited at static deposition mode demonstrate more homogenous in thickness and resistivity across the target surface compared with conventional rectangular targets. The films deposited under the proper conditions show a regular cone-shaped grain surface and densely packed columnar structure. The minimum resistivity of 3.16 × 10−4Ω·cm was obtained for the film prepared at substrate temperature of 150°C, gas pressure of 640 MPa and oxygen partial pressure of 34 MPa.