Inelastic electron tunneling spectroscopy study of ultrathin AI_2O_3-TiO_2 dielectric stack on Si

摘要

We report the properties of an ultrathin AI_2O_3-TiO_2 dielectric stack with the equivalent-oxide thickness =1.0 nm. The stack exhibits nondiscernable interfacial layer on Si, and absence of serious AI_2O_3-TiO_2 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 AI_2O_3-TiO_2 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.