Comparative study on the charge-trapping properties of TaAlO and ZrAlO high-k composites with designed band alignment

The charge-trapping memory (CTM) structures Pt/Al2O3/TaAlO/Al2O3/p-Si and Pt/Al2O3/ZrAlO/Al2O3/p-Si were fabricated by using rf-sputtering and atomic layer deposition techniques, in which the potentials at the bottom of the conduction band (PBCB) of high-k composites TaAlO and ZrAlO were specially designed. With a lower PBCB difference between TaAlO and p-Si than that between ZrAlO and p-Si, TaAlO CTM device shows a better charge-trapping performance. A density of trapped charges 2.88 × 1013/cm2 at an applied voltage of ±7 V was obtained for TaAlO CTM device, and it could keep about 60% of initially trapped charges after 10 years. It was suggested that the PBCB difference between high-k composite and p-Si dominates their charge-trapping behaviors.