Higher-K formation in atomic layer deposited Hf_1-xAl_xO_y

Abstract

We have successfully deposited ALD Hf1-xAlxOy with Al/(Al+Hf)% ranging from 0 to 25% using a sequential precursor pulse method. The crystal phase was confirmed to be a mixed phase of tetragonal with monoclinic using a combination of synchrotron measurement techniques consisting of grazing incidence X-ray diffraction, and grazing incidence extended X-ray absorption fine structure. We observed an enhancement in electrical properties near the crystallization temperature of the Hf1-xAlxOy films. In addition, the leakage current was also reduced by a factor of 10 while maintaining a flat-band voltage that is comparable to post deposition annealed (PDA) HfO2 films processed under identical conditions. An EOT reduction of ∼2Å EOT with lower gate leakage was obtained for devices with post deposition anneal near the crystallization temperature of the Hf1- xAlxOy films.