AC hot-carrier degradation in a voltage controlled oscillator

It is pointed out that a voltage controlled oscillator can be a useful supplement to ring oscillators for studying AC hot-carrier-induced degradation. AC stress is carried out with a fixed gate voltage while the drain voltage rises and falls. It is found that device parameters degrade under AC stressing with the same time and voltage dependence as under DC stress, suggesting that the same mechanism(s) are at work. Oscillator frequency degradation is correlated with device degradation produced by AC or DC stressing.<>