Structural and stoichiometric change in nitrided HfO₂ grown on Ge(100) by atomic layer deposition

The electronic structure and stoichiometric characteristics of postnitrided HfO₂ grown on Ge(100) were investigated by various physical measurements. N incorporation in HfO₂ grown on Ge was strongly related to the diffusion of Ge from Ge substrate into the film by the postannealing treatment in an NH₃ ambient. The diffusion of Ge into the HfO₂ film was influenced by the formation of GeO_x and GeO_xN_y in the interfacial region. The small amount of N was incorporated into the film at a nitrided temperature of 600°C, while much larger amounts of N atoms were incorporated into the interfacial layer to form GeON at a temperature of 700°C, resulting in the suppression of the diffusion of Ge into the film. However, the interfacial nitrided layer was not stably maintained during the postnitridation anneal, resulting in an enhanced interdiffusion of Ge and Hf into the film.