Study On The Structure And Reliability Of Deep Submicrion SDE MOSFET

The Source Drain Extension (SDE) structure and its reliability are thoroughly studied. First, it is shown that the SDE structure can suppress short channel effect effectively and the parasitic resistance at the SDE region has an effect on performance. It is proposed that increasing the dose condition in the SDE region can reduce the parasitic resistance and should be adopted to achieve high performance for deep submicron devices.Second, the hot carrier induced degradation in SDE structures is deeply analyzed. The experiments results have shown that the degradation of SDE structures shows different characteristics. The degradation nature is studied and an explanation is given. It is shown that substrate current is not the good indication of hot carrier effect in SDE structures and using a threshold degradation criterion to characterize device degradation is not suitable for SDE structures.Third, the effect of the SDE implant dose on the hot carrier immunity is thoroughly studied. It is proposed that the higher dose condition creates more hot carriers but the lower sensitivity to hot carrier effect. Therefore, the optimum dose for reliability is determined from the trade-off between the above two aspects. Finally, a simple model is proposed and discussed.