Device scaling effects on hot-carrier induced interface and oxide-trapped charge distributions in MOSFETs

Abstract

The influence of channel length and oxide thickness on the hot-carrier induced interface (N_it) and oxide (N_ot) trap profiles is studied in n-channel LDD MOSFET's using a novel charge pumping (CP) technique. The technique directly provides separate N_it and N_ot profiles without using simulation, iteration or neutralization, and has better immunity from measurement noise by avoiding numerical differentiation of data. The N_it and N_ot profiles obtained under a variety of stress conditions show well-defined trends with the variation in device dimensions. The N_it generation has been found to be the dominant damage mode for devices having thinner oxides and shorter channel lengths. Both the peak and spread of the N_it profiles have been found to affect the transconductance degradation, observed over different channel lengths and oxide thicknesses. Results are presented which provide useful insight into the effect of device scaling on the hot-carrier degradation process.