The columnar morphologies commonly found in all vapor-deposited thin films prepared under low mobility conditions have been classified by several variations of what have been termed structure zone models. Such morphological structures are found to have a strong similarity in shape and form over six orders of magnitude in film thickness and three orders of magnitude in magnification for films of a given thickness. Thick (45-mm) pyrolytic graphite films are shown to be a good demonstration of the continuous growth evolution of conical-shaped units. Due to competition for growth each cone eventually goes through a death stage. A model based upon these general structural observations is presented and is shown to be a geometric construction similar to a Sierpinski gasket. The origin of this morphology seems to be the natural clustering which occurs due to the random process of ballistic aggregation.
Amorphous germanium thin films were prepared by electron-beam evaporation with low-energy Ar ion assist. The ion energy and ion/atom arrival rate ratio were varied from 15 to 110 eV and between 0% and 25%, respectively. The low-density "void" network structure was observed by transmission electron microscopy and characterized by spectroscopic ellipsometry. The void content of the films was shown to depend strongly on the ion/atom arrival rate ratio and to a lesser extent on the incident ion energy. A more quantitative description of thin-film evolution and important factors which affect it are discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.