Property Improvement of CTF Memories Utilizing Hybrid Tunnel Oxide

Various hybrid tunnel oxides in both MANOS structure and SONOS structure were examined. Among them, SiO
₂
/ZrO
₂
hybrid tunnel oxide in charge trap flash memory provides promising programming characteristics compared to those of SiO
₂
tunnel oxide. However, the relatively higher Fowler-Nordheim tunneling barriers for the hole result in insufficient erasing characteristics. In contrast, Si
_2-X
ON
_X
/ZrO
₂
hybrid tunnel oxide could be erased to negative Vth. In addition, the retention behaviors of the hybrid tunnel oxides based on an high temperature storage (HTS) test were superior compared to that of SiO
₂
tunnel oxide. The cycle characteristics in endurance and HTS of Si
_2-X
ON
_X
/ZrO
₂
hybrid tunnel oxide were confirmed to be better than those of Si
_2-X
ON
_X
tunnel oxide, which implies that they satisfy real operational conditions. Thus, Si
_2-X
ON
_X
/ZrO
₂
hybrid tunnel oxide can be a promising candidate for a next-generation tunnel oxide.