A new method for characterizing the spatial distributions of interface states and oxide-trapped charges in LDD n-MOSFETs

Previous studies showed that simultaneous determination of the interface states (Nit) and oxide-trapped charges (Q/sub ox/) in the vicinity of the drain side in MOS devices was rather difficult. A new technique which allows a consistent characterization of the spatial distributions of both hot-carrier-induced Nit and Q/sub ox/ is presented. Submicron LDD n-MOS devices were tested and charge pumping measurements were performed. The spatial distributions of both Nit and Q/sub ox/ have been justified by two-dimensional (2-D) device simulation of the I-V characteristics for devices before and after the stress. Comparison of the drain current characteristics between simulation and experiment shows very good agreement. Moreover, results show that fixed-oxide charge effect is less pronounced to the device degradation for the experimental LDD-type n-MOS devices.