Geometry effects on the NBTI degradation of PMOS transistors

This paper presents the real impact of transistor geometry on the NBTI degradation. I_Dsat degrades faster longer transistors, which is attributed to the small relative saturation region with respect to the total channel length. Narrow transistor degradation is accelerated by the contribution of the edge of the active region. Transistor lifetime depends on their width in a logarithmic way. It also explain the instability observed in measurements on small area transistors by the impact of very few defects relaxation during the measurements. Low voltage P-channel MOSFETs with various channel lengths and widths are used in this study. According to this work, the worst case for NBTI degradation would be a narrow and long transistor.