Degradation of the front and back channels in a deep submicron partially depleted SOI NMOSFET under off-state stress

摘要

The hot-carrier effect characteristic in a deep submicron partially depleted SOI NMOSFET is investigated. Obvious hot-carrier degradation is observed under off-state stress. The hot-carrier damage is supposed to be induced by the parasitic bipolar effects of a float SOI device. The back channel also suffers degradation from the hot carrier in the drain depletion region as well as the front channel. At low gate voltage, there is a hump in the sub-threshold curve of the back gate transistor, and it does not shift in the same way as the main transistor under stress. While under the same condition, there is a more severe hot-carrier effect with a shorter channel transistor. The reasons for those phenomena are discussed in detail.