Reliability Improvement of Gate-All-Around Junctionless SONOS Memory by Joule Heat From Inherent Nanowire Current

Endurance to cyclic program/erase (P/E) was experimentally improved by Joule heat from inherent nanowire current I-nanowire in a gate-all-around (GAA)-based junctionless (JL) silicon channel (S), tunneling oxide (O), charge trap nitride (N), blocking oxide (O), and poly-silicon gate (S) (SONOS) flash memory. Bulk conduction in the JL structure is favorable to flow I-nanowire across a source and a drain to generate Joule heat for electro-thermal annealing (ETA). Increased temperature ( T ) arising from Joule heat was utilized to cure the damage caused by iterative P/E operations. To quantitatively evaluate the level of induced damage by P/E cycling and cured damage by Joule heat, border trap density (N-bt ) in a tunneling oxide was analyzed through low-frequency noise (LFN) measurements. Stress-induced leakage current (SILC), which is related to bulk trap density ( N-bulk ), was measured and compared before and after ETA. The operation-induced damage was mostly recovered by ETA, which does not require any structural change to drive Joule heat or to make an extra nanoheater.