TURN-AROUND EFFECTS DURING DYNAMIC OPERATION IN 0.25μm CMOS TECHNOLOGY FROM LOW TO HIGH TEMPERATURE

摘要

The hot-carrier reliability of a 0.25μm CMOS technology with a 5nm-thick gate-oxide is studied from low (-40℃) to high temperature (125℃). Channel hot-carriers are investigated using DC and AC experiments on single transistors and on ring oscillators. Turn-around effects are observed in the degradation of the ring oscillator frequency at short times when P-MOSFET's degradation totally compensate the N-MOSFET's current reduction. As the electron trapping becomes much less efficient in thin gate-oxide P-MOSFET's with respect to field enhanced detrapping, the influence of the generated interface traps dominates leading to a cumulative current reduction in both device types at long stress time which results in a reduction of the oscillator frequency. The degradation behavior of the oscillator frequency exhibits a clear dependence on the P-MOSFET channel- width and on temperature as negative bias temperature instability occurs at 125℃ during the high state in P- MOSFET's and the field-assisted discharge of electron traps occurs at -40℃.