Improved retention characteristic of charge-trapped flash device with sealing layer/Al_2O_3 or Al_2O_3/high-k stacked blocking layers

摘要

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.