Atomic layer deposition (ALD) is an extension of the Atomic Layer Epitaxy (ALE) technique that was patented in the 1970's (U.S. Patent 4058430, 1977), by Tuomo Suntola working for the Instrumentarium Oy Company in Espoo, Finland. The first published article referring of the ALE process was in 1980 in Thin Solid Films v.65 pp.301-307, authored by M. Ahonen, M. Pessa, and T. Suntola, which focused on ZnTe materials which were of interest for applications in electroluminescent flat-panel displays. The ALE (and ALD) process involves a sequential set of self-limiting surface reactions, as shown in the adjacent schematic figure. It is the self-limiting nature of each reaction step that differentiates ALE and ALD from other more common chemical vapor deposition technologies. Ahonen et al. make clear this unique attribute of ALE by saying "... a thermodynamic equilibrium of the surface is approached at the end of each reaction step--a situation that is usually not met in other evaporation methods."

By the mid 1990's ALD was being studied by several researchers, most notably groups in Helsinki University of Technology, the University of Helsinki, and the University of Colorado. ALD technology grew rapidly in the late 1990's and early 2000's when the electronics industry began to consider it for manufacturing of ultra-thin gate dielectrics for advanced metal-oxide-semiconductor transistors. Currently there are many groups world-wide studying various aspects and new applications for ALD.

Our research group is actively studying low temperature ALD processes, especially for applications in coating of large surface-area structures including fiber and fibrous mat systems.