Self-assembled Ge/Si hetero-nanocrystals for nonvolatile memory application

In this work, Ge/Si hetero-nanocrystals are used as floating gates for nonvolatile memory application. The nanocrystals were fabricated by Ge selective growth on Si nanocrystals in a chemical vapor deposition system. The scanning electron microscopy measurement affirms the density and size of the nanocrystals to be 6 × 1011 cm− 2 and 7 nm, respectively. Metal-oxide-semiconductor memory with Ge/Si hetero-nanocrystals and Si nanocrystals were fabricated and characterized. Significant hole retention enhancement was observed in Ge/Si hetero-nanocrystal memory. This performance enhancement is attributed to the quantum well formed between Ge and Si valance band, where holes are preferentially stored.