Barna and Adamik [3] set the boundaries slightly differently and introduced a transition zone T between zones 1 and 2. In this transition zone, for 0.2 0.4 h T < < , surface diffusion is “remarkable” but grain boundary diffusion is strongly limited leading
to competitive grain growth and resulting in V-shaped grains with a grain structure that is not homogenous through the film thickness. They stressed that a more realistic SZD
should include process-induced segregation of co-deposited impurities or additive
species. This qualification is an example that the simplistic representation of a SZD does not include all parameters, and that a SZD may not be directly applicable to a material a researcher is interested in. It is also emphasized that SZDs are designed to illustrate the microstructure of relatively thick films, i.e., those that are grown much beyond their nucleation phase.