Edge and floating body effects on hot-carrier-induced degradation in FD SOI n-MOSFETs

In this paper, the edge and floating body effects on hot-carrier-induced degradation in fully depleted SOI n-MOSFETs are studied. It is shown that the parasitic bipolar transistor action and the average impact ionization rate at low gate bias are higher for wider MOSFETs. Furthermore, the efficiency of the body contact is larger in the case of narrow devices and cannot suppressed the action of the parasitic bipolar transistor. The result is that wider devices are more degraded in the front and back channels under an identical stress condition for both a floating and a grounded body. We also show that the edge effects are attenuated in Unibond devices which are more resistant to hot-carrier injection than SIMOX MOSFETs.