In order to investigate charge trap characteristics with various thicknesses of blocking and tunnel oxide for application to non-volatile memory devices, we fabricated 5 and 15nm Al 2 O 3 /5nm La 2 O 3 /5nm Al 2 O 3 and 15nm Al 2 O 3 /5nm La 2 O 3 /5, 7.5, and 10nm Al 2 O 3 multi-stack films, respectively. The optimized structure was 15nm Al 2 O 3 blocking oxide/5nm La 2 O 3 trap layer/5nm Al 2 O 3 tunnel oxide film. The maximum memory window of this film of about 1.12V was observed at 11V for 10ms in program mode and at −13V for 100ms in erase mode. At these program/erase conditions, the threshold voltage of the 15nm Al 2 O 3 /5nm La 2 O 3 /5nm Al 2 O 3 film did not change for up to about 10 4 cycles. Although the value of the memory window in this structure was not large, it is thought that a memory window of 1.12V is acceptable in the flash memory devices due to a recently improved sense amplifier.