Enhanced charge trapping characteristics through composite high-k material phase separation

Abstract

Charge trapping memory with the P-Si/Al2O3/LaTiO/Al2O3/Pt structure was fabricated by a pulsed laser deposition system. An innovative high-k nanocrystal-amorphous phase structure could be stably formed in the charge trapping layer. The La2O3 nanocrystals are embedded in amorphous TiO2. Numerous charge traps are generated at the phase interface, which could significantly increase the charge trapping capability. A larger memory window of 16.56 V at ±12 V sweep voltage is observed, comparing with a lower value of 5.52 V for the simple amorphous structure. The device also demonstrated excellent stability, with only a 13% charge loss rate after 10 years and an unchanged memory window after 105 program/erase cycles. It is attributed to the structure that the amorphous phase isolates the trapped electrons around the nanocrystal and, thus, is resistant to loss. This work could provide an approach to generating charge traps by phase separation of high-k materials for future nonvolatile memory applications.