Dielectric properties and charge storage characteristics of the metal-TiO2-SiO2-Si structure

Semiconductor memory elements have been fabricated on silicon utilizing electron-beam evaporated TiO₂ as the charge storage insulator medium. The dielectric and charge storage properties of TiO₂ films have been characterized as a function of TiO₂ deposition conditions and post-deposition annealing. Our results show that both dielectric constant and charge storage properties are enhanced by evaporation of the TiO₂ in an oxygen ambient and substrate heating during evaporation. Post-deposition annealing in an oxygen ambient is also shown to increase the dielectric constant. M-TiO₂-SiO₂-Si structures with a 1000 Å layer of TiO₂ typically exhibit 5 V memory windows for a ±15 V write/erase pulse.