Additional scattering effects for mobility degradation in Hf-silicate gate MISFETs

By controlling the crystallization in Hf-silicate gate dielectrics, we directly observed that the crystallized-HfO/sub 2/ portions in Hf-silicate degrade the electron mobility in Hf-silicate gate MISFETs. The degradation is proportional to the amount of crystallized portions in the Hf-silicate, which induce Coulomb scattering, in addition to substrate impurity scattering. Furthermore, we quantitatively investigated the contributions of the additional scattering to the electron mobility in Hf-silicate gate MISFETs.