A comparative study of tunneling, substrate hot-electron and channel hot-electron injection induced degradation in thin-gate MOSFET´s

The comparison of Fowler-Nordheim tunneling substrate hot-electron and channel hot-electron injection induced degradation in n-channel MOSFET´s has been studied through the use of three different gate dielectrics of 15nm thickness (oxide nitrided-oxide and reoxidized nitrided oxide). Their respective degradation rate and spectrum of generated interface states are characterized by combining quasi-static CV and MOSFET subthreshold methods. Depending on the particular stressing configuration and film used, either one or two interface-state peaks located at 0.1eV and 0.35eV above midgap can be observed. In general, no direct correlation is found among the three stressing configurations (F-N., SHE and CHE) indicating somewhat different physical mechanisms are involved in each case. These results suggest that the comparison in film properties obtained from one stressing configuration cannot generally be directly applied to other configurations, and the optimization of gate dielectric will be application-dependent.