The effects of duty cycle and voltage swing of gale pulse on the AC-stress-induced degradation of nMOSFETs with N2O gate oxides

AC-stress-induced degradation in metal-oxide-semiconductor field-effect tra nsistor (MOSFET) with N2O-grown and N2O-nitrided gate oxides was investigat ed, with emphasis on the duty cycle and voltage swing of the gate pulse. It is demonstrated that N2O-oxide devices show a weaker duty-cycle dependence than thermal-oxide devices, with N2O-nitrided oxide superior to N2O-grown oxide. More significantly, opposite frequency dependence of the V-T shift i s found between gate-pulse swings of 0-1/2 V-D and 0-V-D. The reasons are l ikely due to charge trapping and neutral-trap creation in the gate oxide. ( C) 1998 Elsevier Science Ltd. All rights reserved.