Toward quantification of thin film morphology

Abstract

Before any meaningful quantitative understanding of thin film growth morphology can be developed, a sufficiently detailed model must be established. For the case of films deposited under low mobility conditions, the model of the internal void networks, which are the morphology, is a fractal construction based upon the random competition for cone growth. The origin of the development of cones is a natural consequence of the random ballistic aggregation process. Both current and future approaches to quantitative measurement of this morphological model are discussed and include a series of direct (scanning electron, transmission electron, and field ion and optical microscopy) and indirect (spectroscopic ellipsometry, image enhancement and analysis of morphology photographs, small angle x-ray and electron scattering, and computer simulations of film growth) characterization techniques. It is shown how quantitative preparation–property relations in thin films will have to first start with a quantitative description of the film morphology.