Impact of Channel Hot-Hole Stressing on Gate-Oxide Trap's Emission

Fluctuating parametric shifts that arise from the stochastic capture/emission by oxide traps in small gate-area MOSFETs have triggered considerable interest due to their impact on timing-sensitive circuits. To date, studies have only reported the effect of gate voltage stress on oxide traps, while the effect of drain voltage stress is equally important but is seldom studied. This work examines the impact of channel hot-hole (CHH) stress on oxide traps in a nanoscale p-MOSFET. A change in the traps' emission time constants under operating gate voltage is observed after the CHH stress. Traps which are relatively inactive (capture once and does not emit within the measurement timeframe) may be rendered much more active (exhibit many capture and emission events) after the CHH stress due to a decrease in the emission time constant. On the other hand, traps which are active may become inactive after the CHH stress due to an increase of the emission time constant. Reversion to the pre-CHH-stress behavior is observed after extended rest under unbiased condition. The traps could then undergo similar changes in emission behavior when the CHH stress is reapplied.