Inelastic electron tunneling spectroscopy study of ultrathin Al2O3-TiO2 dielectric stack on Si

Abstract

We report the properties of an ultrathin Al2O3-TiO2 dielectric stack with the equivalent-oxide thickness=1.0 nm. The stack exhibits nondiscernable interfacial layer on Si, and absence of serious Al2O3-TiO2 intermixing. Inelastic electron tunneling spectroscopy (IETS) has been used to provide a wealth of information concerning the phonons, bonding vibration modes, and traps in the Al2O3-TiO2 gate dielectric stack as well as its interfaces in a metal-oxide-Si structure. The IETS spectra before and after forming gas annealing suggest that the reduction of traps is related to the formation of Si-H bonds at the oxide-Si interface. (C) 2010 American Institute of Physics. [doi:10.1063/1.3518478]