New observation and improvement in GIDL current of N-MOSFET's with various kinds of gate oxides under hot-carrier stress

Abstract

Degradation in gate-induced drain leakage (GIDL) current of n-MOSFET's with conventional SiO2 and oxynitride as gate dielectrics under hot-carrier stresses at different gate voltages is investigated. It is found that the shift of GIDL current is very sensitive to gate voltage and is maximum under a stress with VG = 0.5 VD even for a short stress time. This might result from hot electrons captured by fast acceptor-like interface states, thus revealing that the quality of the Si/SiO2 interface is an important factor on the reduction of GIDL shift under hot-carrier stress. Unlike conventional gate-oxide devices, the degradation can be greatly suppressed in nitrided-oxide devices, especially reoxidized-nitrided-oxide devices due to the considerably improved quality of both the gate oxide and Si/SiO2 interface by thermal nitridation and ensuing reoxidation.