Effect of atomic layer annealing in plasma-enhanced atomic layer deposition of aluminum nitride on silicon

Abstract

The effect of adding an atomic layer annealing step to a plasma-enhanced atomic layer deposition process of aluminum nitride was investigated with commonly available materials. The refractive index, crystallinity, stoichiometry, and impurity concentrations were studied from films grown from trimethylaluminum and ammonia precursors at 300°C on Si(111) substrates. Additional energy provided by the atomic layer annealing step during each deposition cycle was found to enhance the crystallinity and stoichiometry and increase the refractive index and film density. A polycrystalline hexagonal film with a weak c-axis orientation was obtained on substrates with and without native oxide, which is promising for applications that require high quality films at low temperatures.