GREATLY SUPPRESSED STRESS-INDUCED SHIFT OF GIDL IN N2O-BASED N-MOSFETS

Considerably suppressed gate-induced drain leakage (GIDL) shifts of N2 O-based n-MOSFET's after hot-carrier stress with different gate voltag es are observed. The mechanisms involved are studied by dividing gate- oxide traps into sub-interface and bulk-oxide traps, and by means of c omputer simulations on electric-field distribution and carrier filling of these traps. It is demonstrated that sub-interface and bulk-oxide hole detrapping during stressing are mainly responsible for the respec tive GIDL shifts under two different stress conditions of V-G=0.5V(D) and V-G=V-D, with the effect of the former larger than the latter. In view of this, it is proposed that MOSFET's with N2O-nitrided or especi ally N2O-annealed NH3-nitrided gate oxide have not only fewer pre-exis ting sub-interface and bulk-oxide hole traps, but also greatly suppres sed generation of hole and neutral electron traps due to the formation of a nitrogen-rich layer near the SiO2/Si interface through N2O treat ment. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.