Memory Effect of Metal-Insulator-Silicon Capacitor with HfO 2 -Al 2 O 3 Multilayer and Hafnium Nitride Gate

Metal-insulator-silicon capacitors have been fabricated using novel insulators of SiO 2 /HfO 2 -Al 2 O 3 -HfO 2 (HAH)/Al 2 O 3 and metallic HfN gate, exhibiting a program-erasable characteristic. The memory capacitor presents a large memory window of 2.4 V under +12 V program/–14 V erase for 10 ms, no erase saturation, and sufficient electron- and hole-trapping efficiencies such as an electron density of ∼7 × 10 12 cm –2 under 13 V program for 0.5 ms and a hole density of ∼4 × 10 12 cm –2 under –12 V erase for 0.5 ms. The observed properties are attributed to the introduction of high permittivity atomic-layer-deposited HAH/Al 2 O 3 as well as high work function HfN gate. The related mechanism is addressed accordingly.