Synthesis of graded Hf-silicate thin films for alternate gate dielectric applications

The dielectric and material properties of compositionally graded Hf-silicate films are reported. The graded Hf-silicate films were processed at ∼400°C by pulsed-laser deposition and ultraviolet-radiation-assisted oxidation technique. The relative HfSi content in the films was increased upward from the Si substrate, gradually changing the bonding from Hf-rich silicate at the top layers to Hf-poor silicate bonding and at the film-Si interface, respectively. The graded Hf-silicate films exhibited a dielectric constant of 14.7 and were found to remain amorphous after a rapid thermal anneal at 1000°C.