Scaling behavior and structure transition of ZrO2 films deposited by RF magnetron sputtering

ZrO2 thin films were deposited onto Si wafers and glass slides by reactive rf magnetron sputtering with varying conditions of substrate temperature (T-s). Structural analysis was carried Out using high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM). The scaling behavior of the AFM topographical profiles was analyzed using one-dimensional power spectral density method (1DPSD). Morphological and structural evolution of ZrO2 films have been studied in relation to T-s. With substrate temperatures ranging from RT to 550 degrees C, the structural transition of the films is a-ZrO2 (below 250 degrees C) -> m-ZrO2 with a little a-ZrO2 (450 degrees C) -> m-ZrO2 with a little t-ZrO2 (550 degrees C). The roughness exponent alpha is 1.53 +/- 0.02.1.04 +/- 0.01,1.06 +/- 0.05,1.20 +/- 0.03 for ZrO2 thin films deposited at RT, 250 degrees C, 450 degrees C, and 550 degrees C, respectively. Quantitative surface characterization by spatially resolved 1DPSD analyses identified three different growth mechanisms of surface morphology for ZrO2 thin films deposited at RT, 250 similar to 450 degrees C and 550 degrees C. The evolution and interactions of surface roughness and microstructure are discussed in terms of surface diffusion, grain growth, and flux shadowing mechanisms. (C) 2009 Elsevier Ltd. All rights reserved.