Effects of triple blocking layers on operation performance in charge-trapping flash devices

Although retention characteristic of charge trapping (CT) flash device is improved by using Al
₂
O
₃
/HfO
₂
blocking layer, the electron back tunneling (EBT) during erasing is still an issue. In order to overcome this issue, CT flash devices with triple blocking layers of either high/low/high (HLH) or low/high/low (LHL) electron energy barrier structures are proposed in this work. Programming, erasing, and retention characteristics of CT flash device can be enhanced by these triple blocking layers. In addition, CT flash device with Al
₂
O
₃
/HfAlO/Al
₂
O
₃
triple blocking layer has the most excellent data retention and good programming speed.