EFFECT OF PROTON-INDUCED DAMAGE ON THE PERFORMANCE OF ENHANCEMENT-MODE MOSFET

The present study of MOSFET takes into account the influence of displa cement damage induced carrier removal phenomenon occurring below the g ate and trapped charge build-up within the oxide layer after proton ir radiation. In reference to this, Poisson equations considering proton- induced impurity profile in device channel and trapped concentration w ithin the oxide, have been solved analytically in both the regions. Ac cordingly, the proton-induced expressions of source to drain current-v oltage characteristic, channel conductance, transconductance and thres hold voltage, have been established. The calculated results predict th at the oxide trapped charges get annealed very quickly and are, theref ore, dominant over carrier removal phenomenon at lower temperature pro ton bombardment, whereas the carrier removal phenomenon renders signif icant impact at higher temperature ion exposure in terms of stretched- out effect on the device characteristics. Therefore, this phenomenon c annot be ignored even in MOS devices as has been indicated by previous workers.