US Patent 7554161 HfAlO

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.