Tunneling and thermal emission of electrons from a distribution of deep traps in SiO/sub 2/ (nMOSFET)

Both field-induced, or tunneling, and thermal emission of electrons from deep traps in the gate oxides on n-channel LDD CMOS devices have been observed and characterized. Experimental results show that the deep trapping effects at room temperature are similar to the shallow-level trapping effects observed by others below room temperature. In this case, however, the time constants involved are very long. This model and physical mechanisms can explain the apparent saturation observed under AC stress conditions, and also the differences observed between AC use conditions and DC stress.>