Improved memory window for Ge nanocrystals embedded in SiON layer

The formation of germanium (Ge) nanocrystals embedded in silicon oxygen nitride (SiON) is proposed for charge storage elements in this work. The Ge nanocrystals can be nucleated after the oxidation process of silicon germanium nitride (SiGeN) layer at high temperatures. Compared to the control samples of Ge nanocrystals/SiO2∕Si structure and SiON∕Si stack memory, the proposed Ge nanocrystals/SiON∕Si memory obtained superior memory window, even larger than the typical sum of both. It is considered that the extra interface trap states between Ge and SiON film were generated as Ge nanocrystals were embedded in SiON layer.