Fluctuations in global surface scaling behavior in sputter-deposited ZnO thin films

Quantitative analysis of the roughness scaling behavior, which is critical in understanding the evolution of surface microstructure, is reported for ZnO thin films grown by RF magnetron sputtering. The strong dependence of global and local growth parameters on the applied RF powers can be highlighted as a unique observation, which has not been available from the typical super-rough scaling studies. For example, the global growth exponent increased from 0.53 ± 0.02 at 75 W to 1.03 ± 0.01 at 200 W. The observed dominant anisotropic growth of crystallites at high powers is believed to be the main reason for the power-dependent roughening behavior.