Charge Trapping in Hafnium Silicate Films with Modulated Composition and Enhanced Permittivity
Résumé
Hafnium silicate dielectric films were fabricated by radio frequency magnetron sputtering. Their microstructure and electrical properties were studied versus annealing treatment. The evolution of microstructure and the formation of alternated HfO2-rich and SiO2-rich layers were observed and explained by surface directed spinodal decomposition. The stable tetragonal HfO2 phase was formed upon an annealing at 1000-1100°C. The control of annealing temperature allowed the memory window to be achieved and to be tuned as well as the dielectric constant to be enhanced.