ALD operates on the principle of self-limiting surface reactions. The process comprises alternating pulses of precursor gases that react with the surface in a controlled manner. A typical ALD cycle includes:
Precursor Pulse: A precursor gas is introduced, which reacts with the substrate surface to form a monolayer. Purge: The reaction chamber is purged with an inert gas to remove excess precursor and by-products. Reactant Pulse: A second reactant gas is introduced to react with the adsorbed precursor layer, forming a thin film. Second Purge: Another purge step removes excess reactants and by-products.
