Nonvolatile Memory With Ge/Si Heteronanocrystals as Floating Gate

A p-channel memory with Ge/Si heteronanocrystals (HNCs) as the floating gate was fabricated and tested. The nanocrystals (NCs) were synthesized by low-pressure chemical vapor deposition of Si NCs followed by selective growth of Ge on top of Si. Both hole and electron storages were characterized in Ge/Si HNC memory. Fowler-Nordheim and hot carrier injection programming operations were studied. Compared to Si NC memory, enhanced memory performances were demonstrated in Ge/Si HNC memory in terms of longer retention, larger storage capability, and faster programming.