In₂O₃ Nanocrystal Memory with the Barrier Engineered Tunnel Layer

In₂O₃ nanocrystal memories with barrier-engineered tunnel layers were fabricated on a p-type Si substrate. The structure and thickness of the barrier-engineered tunnel layers were SiO₂/Si₃N₄/SiO₂ (ONO) and 2/2/3 nm, respectively. The equivalent oxide thickness of the ONO tunnel layers was 5.64 nm. The average size and density of the In₂O₃ nanocrystals after the reaction between BPDA-PDA polyimide and the In thin film were about 8 nm and 4 × 10¹¹ cm⁻², respectively. The electrons were charged from the channel of the memory device to the quantum well of the In₂O₃ nanocrystal through the ONO tunnel layer via Fowler–Nordheim tunneling. The memory window was about 1.4 V when the program and erase conditions of the In₂O₃ nanocrystal memory device were 12 V for 1 s and −15 V for 200 ms.