Conventional SONOS (poly-silicon/oxide/nitride/oxide/silicon) type memory is associated with a retention issue due to the continuous demand for scaled-down devices. In this study, Al2O3/Y 2O3/SiO2 (AYO) multilayer structures using a high-k Y2O3 film as a charge-trapping layer were fabricated for nonvolatile memory applications. This work focused on improving the retention properties using a Y2O3 layer with different tunnel oxide thickness ranging from 3 nm to 5 nm created by metal organic chemical vapor deposition (MOCVD). The electrical properties and reliabilities of each specimen were evaluated. The results showed that the Y2O 3 with 4 nm SiO2 tunnel oxide layer had the largest memory window of 1.29 V. In addition, all specimens exhibited stable endurance characteristics (program/erasecycles up to 104) due to the superior charge-trapping characteristics of Y2O3. We expect that these high-k Y2O3 films can be candidates to replace Si3N4 films as the charge-trapping layer in SONOS-type flash memory devices.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites