Revisiting structure-zone models for thin-film growth

Abstract

More than 20 years ago Movchan and Demchishin published their structure zone model (SZM) of thin film morphology as a function of a single macroscopic parameter, the normalized substrate temperature. In all its simplicity, this model already reflects many experimental observations of thin film growth with surprising accuracy. Later modifications of the model which included the influence ofresidual gas pressure and electrical bias potential in sputtering extended its validity to this family of deposition processes. Evolutionary features of thin film growth and the fractal nature of thin film structures were also discussed. None of these previous models, however, providedfor a vitreous, fully dense structure as observed with some ion and plasma assisted deposition processes. In 1988, the author proposed an extension of the original Movchan-Demchishin SZM with afourth zone reflecting the vitreousphase. In thispaper, we will discuss the validity ofthis extension and generalize the 4-zone model.