Atomic layer deposition (ALD) is mostly known to produce perfect films with atomic resolution on large substrates and even on complex geometries. This is true for several processes, but not all...
ALD is a chemical process where the film grows on available active sites on a substrate. It has proven capable to grow on surfaces one initially would assume to be inert, such as Teflon and gold. The initial stages of such growth deviates from the ideology of a layered growth. How does this affect the evolution in growth? ALD can produce materials with textures varying from completely amorphous to well crystalline, and their growth dynamics can lead to an evolution in growth that seemingly disobeys the linear growth process most relates to ALD. The crystal growth dynamics known from PVD processes does not apply in the ALD regime. What are the
factors that determine the evolution in texture? ALD relies on self-terminating surface reactions to secure robust growth. What happens to the robustness if the
bulk of the material is capable of absorbing some of the precursor and act as a reservoir? ALD is most suited for deposition of binary compounds, and has proven well capable for deposition of ternary and quaternary compounds. However, control of stoichiometry is not as straight forward as a simple combination of several binary processes. What controls the deposited stoichiometry? These questions, and possibly many more, will be raised during the current contribution where we explore the boundaries of ALD.