Effect of rapid thermal annealing on Zn 1‐x Cd x O layers grown by radio‐frequency magnetron co‐sputtering

Zn 1‐x Cd x O layers were deposited on the sapphire substrate using the radio‐frequency magnetron co‐sputtering system. The grown Zn 1‐x Cd x O layers were carried out in the post‐annealing treatment for 1 min at the 800 °C oxygen‐ambient by the rapid thermal annealing (RTA) method. X‐ray diffraction (XRD) experiment shows that the Zn 1‐x Cd x O layers are changed from the single phase of the hexagonal structure at 0≤ x ≤0.08 to the double phase of hexagonal‐and‐cubic structure at x =0.13. Thus, the maximum Cd‐composition ratio with the hexagonal structure was found out to be x =0.08. Also, the crystallinity of Zn 1‐x Cd x O layers at x =0.13 was remarkably improved by the RTA annealing treatment. This crystal quality improvement was thought to be associated with the relaxation of the compressive strain remaining in the Zn 1‐x Cd x O layers. Therefore, the results of XRD and transmittance lead that the crystal quality of the Zn 1‐x Cd x O layers forming the hexagonal ZnO phase is better than that forming the cubic CdO phase. Consequently, the reliable formation and the crystallinity of the Zn 1‐x Cd x O layers were achieved by using the RTA method of short‐time thermal‐annealing at the high temperature. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)