EXTRA INTERFACE STATE GENERATION ENHANCED BY FLUORINE IN TUNGSTEN-POLYCIDED METAL-OXIDE-SEMICONDUCTOR DEVICES WITH NITRIDED-OXIDE GATE DIELECTRIC

Interface state generation in oxynitride gate dielectric devices with tungsten-polycide (W-polycide) and polycrystalline silicon (poly-Si) gate structures were investigated. A significant amount of fluorine-induced interface states were detected in W-polycide gate device with nitridation of thermal gate oxide by both the charge pumping technique and capacitance/gate voltage (C/V) measurement. Re-oxidation of oxynitride gate oxide results in partial annealing of these interface states. A model of the fluorine induced strain gradient between silicon dioxide and silicon (SiO2/Si) interface was proposed to explain the extra interface state generation mechanism. (C) 1995 American Institute of Physics.