Comparative analysis of trap-based program/erase behaviors with different tunnel barriers

In this study, we comparatively analyze the trap-based memory characteristics of Oxide-Nitride-Oxide (ONO) devices with different tunnel dielectrics. We fabricated two kinds of ONO devices-one is the conventional single tunnel oxide structure and the other is the bandgap engineered structure in which the modulated tunnel dielectric replaces the single tunnel oxide. The charge storage layer is 9 nm and the blocking oxide is 7 nm in both two kinds of ONO devices. Based on experimental results, we find that the memory speed is promoted to 2∼4 times and 10-year data retention greatly improves in the bandgap engineered device comparing to those in the conventional device. As a result, the bandgap engineered tunnel barrier device embodies both fast P/E operation speeds and excellent long-term data retention characteristics, hence, the bandgap engineered tunnel barrier is expected to conduct performance optimization for the future scaled SONOS flash memory.