Hot-carrier degradation of CMOS inverters and ring oscillators at 77K

摘要

The impact of hot-carrier (HC) stress on CMOS inverters at 77K was examined as a function of temperature. It was found that the degradation in inverter propagation delay was about one order less than that of the device transconductance degradation. Activation energy (EA) of propagation delay exhibited two distinct values from 295K to 77K, with a transition at around 175K for virgin and stressed inverters. The improvement of propagation delay and voltage transfer characteristic (VTC) at 77K compared to 295K was larger for virgin than HC stressed inverters.