A New Interface-Trapped-Charge-Degraded Subthreshold Current Model for Quadruple-Gate MOSFETs

By accounting for the effects of equivalent oxide charges on the flat-band voltage, a novel interface-trapped-charge-degraded subthreshold current model is presented for the quadruple-gate (QG) MOSFETs based on the quasi-3-D scaling equation and Pao-Sah´s integral. It indicates that a thin gate oxide can effectively reduce the subthreshold current degradation caused by the trapped charges. In contrast to the thin gate oxide, a thick silicon film is required to alleviate the subthreshold current degradation caused by the negative trapped charges. For the short-channel behavior, the damaged device with negative and positive trapped charges can decrease and increase subthreshold current roll up caused by the short-channel effects, respectively. Due to computational efficiency, the model can be easily used to explore the hot-carrier-induced current behavior for the fully depleted QG MOSFETs for its memory cell application.