Specific structural factors influencing on reliability of CVD-HfO/sub 2/

Abstract

We report on two key issues for CVD-HfO/sub 2/ gate dielectric which influence their reliability. The first is extrinsic defects, i.e. two types of extrinsic defects which lead to large electrical leakage. The other issue is interfaces inside the film, i.e. stoichiometric interfaces due to Si out-diffusion from the substrate, and interfaces defined by dielectric constant transitions formed by a diffusion mechanism of Si into HfO/sub 2/. Lower Weibull slope /spl beta/ is mainly determined by the distance from the Si substrate to the k-transition interface. Although /spl beta/ becomes smaller due to the k-transition interface, it was clarified to be improved by a single layered silicate without k-transition interface.