Reliability Improvement of Gate-All-Around SONOS Memory by Joule Heat From Gate-Induced Drain Leakage Current

Abstract

Endurance to cyclic program/erase (P/E) in a gate-all-around (GAA)-based SONOS flash memory device is improvedby Jouleheat, whichwas drivenby gate-induced drain leakage (GIDL) current (I-GIDL) with a current level of microamperes. By use of COMSOL simulation, induced temperature (T) by the I-GIDL is higher at the GAA with the ONO gate dielectrics than at a GAA with a thermal gate oxide due to the confined heat inside a silicon nanowire channel wrapped by a relatively thick ONO. Furthermore, T is high enough to cure the damage from the iterative P/E operations. For a quantitative evaluationof the damage level before and after cyclic P/E, border trap density (N-bt) in a tunneling oxide was analyzed with the aid of low-frequency noise (LFN) measurements. The damage was almost fully cured by I-GIDL without an external Joule heater or structural modifications because it is always around a MOSFET.