Dynamic Hot-Carrier Degradation of Fast-Switching CMOS Inverters with Different Duty Cycles

The frequency shift of ring oscillators operated at high power supply voltages exhibits hot-carrier degradation similar to the well-known stress effects measured at single transistors. The predicted duty cycles based on substrate currents generated during the fast switching periods yield results which are in good agreement with the degradation data from ring oscillators and externally switched inverters only for short stress times. For long stress times, however, deviations are reported.