Atomic Layer Deposition
ALD is a surface-controlled layer-by-layer process that results in the deposition of thin films one atomic layer at a time. Layers are formed during reaction cycles by alternately pulsing precursors and reactants and purging with inert gas in between each pulse.
WHAT HAPPENS DURING ALD?
Each atomic layer formed by this sequential process is a result of saturated surface-controlled reactions. For example, a metal precursor pulse of trimethylaluminum (Al(CH3)3) followed by an oxygen reactant pulse (H2O vapor) results in the formation of a layer of aluminum oxide, a metal oxide compound that can be used as a high-k dielectric.
Building devices atom by atom gives us very precise control over the process. Because the ALD process is self-limiting, it results in films with a precise thickness and conformality, even over varied surface topographies. It can be applied to produce different oxides, nitrides or other compounds. ALD provides excellent surface control and can produce thin, uniform and pinhole-free films over large areas by single or tailored multiple layer deposition. Nanolaminates or stacked layers of different materials can also be produced, in a straightforward manner, in the ALD reactor.