Atomic layer deposited HfO2 and HfO2/TiO2 bi-layer films using a heteroleptic Hf-precursor for logic and memory applications

Abstract

HfO₂ films were grown by atomic layer deposition (ALD) using a new heteroleptic hafnium precursor, tert-butoxytris(ethylmethylamido)hafnium (BTEMAH), and ozone. This BTEMAH precursor achieved a very high growth rate and retained excellent thermal stability in electrical performance due to the high film density of the HfO₂ films. Additionally, the structural compatibility between the specific planes of tetragonal HfO₂ and rutile TiO₂ achieved a high dielectric constant (∼29) for HfO₂ films grown on a rutile TiO₂ film. It is demonstrated that this BTEMAH is a very promising precursor for the growth of HfO₂ films for both the applications of a gate oxide and a capacitor dielectric.