Mechanism of GIDL degradation induced by hot-carrier stresses in n-MOSFETs

Abstract

Degradation in Gate-Induced Drain Leakage (GIDL) of n-MOSFETs with different gate oxides under different hot-carrier stresses is investigated. It has been found that the shift of GIDL is very sensitive to gate voltage and reaches the maximum under a stress with VG=0.5VD. Through 2-D simulation of electrical field and carrier distribution near the drain, and the introduction of sub-interface traps concept, a new insight on the mechanisms involved in GIDL shift is proposed, i.e. sub-interface and bulk-oxide hole detrappings during stressing are responsible for the respective GIDL shifts under two typical stresses of VG=0.5VD and VG=VD. Furthermore, it is observed that N2O-nitrided and especially N2O-annealed NH3nitrided n-MOSFETs have much smaller GIDL shift as compared with conventional thermally-oxidized n-MOSFETs, indicating considerably suppressed subinterface and bulk-oxide hole traps in these oxynitrides.