Atomic layer-deposited HfAlO3 films for gate dielectrics

摘要

A dielectric film containing HfAlO₃ and a method of fabricating such a dielectric film produce a reliable gate dielectric having an equivalent oxide thickness thinner than attainable using SiO₂. A gate dielectric is formed by atomic layer deposition employing a hafnium sequence and an aluminum sequence. The hafnium sequence uses HfCl₄ and water vapor. The aluminum sequence uses either trimethylaluminium, Al(CH₃)₃, or DMEAA, an adduct of alane (AlH₃) and dimethylehtylamine [N(CH₃)₂(C₂H₅)], with distilled water vapor. These gate dielectrics containing a HfAlO₃ film are thermodynamically stable such that the HfAlO₃ film will have minimal reactions with a silicon substrate or other structures during processing.