Improved retention characteristic of charge-trapped flash device with sealing layer/Al 2O 3 or Al 2O 3/high- k stacked blocking layers

Abstract

Although programming and erase speeds of charge trapping (CT) flash memory device are improved by using Al 2O 3 as blocking layer, its retention characteristic is still a main issue. CT flash memory device with Al 2O 3/high- k stacked blocking layer is proposed in this work to enhance data retention. Moreover, programming and erase speeds are slightly improved. In addition, sealing layer (SL), which is formed by an advanced clustered horizontal furnace between charge trapping layer and Al 2O 3 as one of the blocking layers is also studied. The retention characteristic is enhanced by SL approach due to lower gate leakage current with less defect. With the combination of SL and Al 2O 3/high- k stacked blocking layer approaches, retention property can be further improved.