Impact of channel dangling bonds on reliability characteristics of flash memory on poly-Si thin films

Abstract

In this letter, we fabricated the poly-Si-oxide-nitride-oxide-silicon (SONOS)-type Flash memories on polycrystalline-silicon thin films and found that dangling bonds presented along the grain boundaries in the channel significantly influence their reliability characteristics in the aspects of charge storage, drain disturbance, and gate disturbance. Employing a powerful defect passivation technique, i.e., NH3 plasma treatment, the charge storage capability was clearly observed to be remarkably improved. Even so, the hydrogenated polycrystalline-silicon thin-film transistors (poly-Si-TFTs) still suffered from serious drain and gate disturbances, which exhibited behaviors that are quite specific and undoubtedly distinct from those observed in the conventional SONOS-type memories on single crystalline substrates.