Voltage acceleration NBTI study for a 90nm CMOS technology

NBTI lifetime data for 10% Idsat shift (and 10% Vtsat shift) vs. stress voltage for different transistor geometries with a nitrided thin gate oxide were measured over a wide range of stress gate voltages. It was found that the voltage acceleration factor increases with decreasing stress voltage resulting in a non-linearity of the log lifetime vs. stress voltage relationship. It was also found that the large area MOSFET exhibits NBTI saturation phenomena after stressing over a long time period before it reaches the 10% Idsat shift lifetime limit criteria. The lifetime vs. PMOSFET geometry will also be discussed in detail.