Transparent Flash Memory Using Single Ta₂O₅ Layer for Both Charge-Trapping and Tunneling Dielectrics

We report reproducible multibit transparent flash memory in which a single solution-derived Ta₂O₅ layer is used simultaneously as a charge-trapping layer and a tunneling layer. This is different from conventional flash memory cells where two different dielectric layers are typically used. Under optimized programming/erasing operations, the memory device shows excellent programmable memory characteristics with a maximum memory window of ∼10.7 V. Moreover, the flash memory device shows a stable 2-bit memory performance and good reliability, including data retention for more than 10⁴ s and endurance performance for more than 100 cycles. The use of a common charge-trapping and tunneling layer can simplify the fabrication of advanced flash memories.