A study of gate-sensing and channel-sensing (GSCS) transient analysis method—Part I: Fundamental theory and applications to study of the trapped charge vertical location and capture efficiency of SONOS-type devices

Abstract—For the first time, we can directly investigate the charge transport and intra-nitride behaviors of SONOS-type devices by exploiting the gate-sensing and channel-sensing (GSCS) method. Our results clearly indicate that for electron injection (+FN program), the electron centroid migrates from the bottom toward the nitride center, whereas for hole injection (−FN erase), holes first recombine with the bottom electrons and then gradually move upward. For the electron de-trapping processes under−VG stressing, the trapped electrons de-trap first from the bottom portion of nitride. We also develop a method to distinguish the electron de-trapping and hole injection erasing methods by comparing the erasing current density (J) versus the bottom oxide electric field (E). At short-term high-temperature baking, the electrons move from the top portion toward the bottom portion, and this intra-nitride transport becomes more significant for a thicker nitride. On the other hand, after long-term bak-ing, the charge loss mainly comes from the bottom portion of nitride. Index Terms—Gate-sensing and channel-sensing (GSCS), GSCS method, intra-nitride charge transport, nitride trap vertical loca-tion, SONOS. I