Enhanced flash memory device characteristics using ALD TiN/Al2O3 nanolaminate charge storage layers

Enhanced flash memory device characteristics using ALD TiN/Al₂O₃ nanolaminate charge storage layers have been investigated. After annealing treatment, the TiN nanocrystals embedded in Al₂O₃ films with a small diameter of ~3 nm and a high-density of >1×10¹²/cm² have been formed. The memory devices show a high programming speed of ¿V_t >1 V@V_g/V_d=8 V/8 V, 10 ¿s and an erasing speed of ¿V_t >1 V@V_g/V_d=-12 V/0 V, 1 ms. The memory window is increased (¿V_t >6.7 V) with increasing the operation voltage. The memory window is also increased with increasing the number of TiN/Al₂O₃ nanolaminate layers. Good endurance (10⁴ cycles) and retention (charge loss of ~14% at 20°C and ~17% at 85°C after 10 years) characteristics of the TiN nanocrystal memory devices can be explained by both of the high-density and layer-by-layer charge storage in the TiN nanocrystals. This novel nanocrystal memory structure can be useful in future nanoscale flash memory device applications.