Change in the chemical state and thermal stability of HfO_(2) by the incorporation of Al_(2)O_(3)

摘要

Al_(2)O_(3) incorporated HfO_(2) films grown by atomic layer deposition were investigated using various measurement tools. The accumulation capacitance of the Al_(2)O_(3) incorporated into HfO_(2) film increases as the postannealing temperature increases because of changes in interfacial and upper layer thickness and in interfacial stoichiometry. The core-level energy state of a 15 A thick film shows a shift to higher binding energy, as the result of silicate formation and Al_(2)O_(3) incorporation. The incorporation of Al_(2)O_(3) into the HfO_(2) film has no effect on silicate formation at the interface between the film and Si, while the ionic bonding characteristics and hybridization effects are enhanced compared to a pure HfO_(2) film. Any dissociated Al_(2)O_(3) on the film surface is completely removed by a vacuum annealing treatment over 850℃, while HfO_(2) contributes to Hf silicide formation on the surface of the film.