ROLE OF NITRIDATION REOXIDATION OF NH3-NITRIDED GATE DIELECTRICS ON THE HOT-CARRIER RESISTANCE OF CMOS TRANSISTORS/

The effect of nitriding and reoxidizing conditions are examined on the hot-carrier (HC) properties of p-channel and n-channel transistors wi th reoxidized nitrided oxide gate dielectrics. Nitrogen was introduced into the gate dielectric by performing cyclical nitridation and reoxi dation steps (one cycle versus four cycles of nit./reox.), keeping the same overall oxidation and nitridation times constant. It was found t hat there were considerable differences in hot-carrier hardness, of up to three orders of magnitude for p-channel transistors, but much less for n-channel devices, Nitrogen-content variations (a factor of 2) fo r these very similar conditions explain the n-channel hot-carrier resu lts. In the case of the p-MOS transistors, it is suggested that change s in hydrogen concentration might be responsible for their hot-carrier behavior.