Charge-trapping devices using multilayered dielectrics were studied for nonvolatile memory applications. The device structure is Al/Y 2 O 3 /Ta 2 O 5 /SiO 2 /Si (MYTOS). The MYTOS field effect transistors were fabricated using Ta 2 O 5 as the charge storage layer and Y 2 O 3 as the blocking layer. The electrical characteristics of memory window, program/erase characteristics, and data retention were examined. The memory window is about 1.6 V. Using a pulse voltage of 6 V, a threshold voltage shift of โผ1 V can be achieved within 10 ns. The MYTOS transistors can retain a memory window of 0.81 V for 10 years
