Performance of SONOS-Type Device with Bandgap Engineering of Charge-Trapping Layers (abstract)

The polycrystalline silicon‐oxide‐nitride‐oxide‐silicon (SONOS) device has become an appealing alternative for next‐generation flash memory applications. However, as nitride thickness and gate size are reduced in nano‐scale, some problems in device performance and reliability have resulted, such as insufficient charge trapping efficiency. To solve these problems, bandgap engineering in charge trapping layers has been proposed for high‐density flash memories. We proposed bandgap engineering technique in SONOS devices to improve device performance. In this work, uniform standard nitride, Si‐rich nitride, and proposed non‐uniform nitride films were fabricated. The modified non‐uniform nitride film has a Si‐rich region in its core, surrounded by standard silicon nitride layers. To evaluate performance, its proposed structure was compared with both standard nitride and Si‐rich nitride structures. We confirmed that our structure could be effective in improving facets of device performance, such as charge trapping efficiency, cycling endurance, and data retention. These results show that the proposed structure is promising for application to next‐generation charge‐trap memory devices.