Synthesis and characterization of a charge storage structure with germanium nanocrystals

Abstract

A study of germanium (Ge) nanocrystal formation in bulk co-sputtered SiO2 + Ge films via rapid thermal annealing (RTA) was first carried out. Next, a novel tri-layer charge storage structure comprising of a rapid thermal oxide layer, followed by a co-sputtered SiO2 + Ge middle layer and a third sputtered capping silicon dioxide (SiO2) layer was fabricated. Ge nanocrystals were formed in the middle layer when RTA at 1000 A?C for 300 s. The formation and evolution of Ge nanocrystals in a tri-layer structure were then investigated. Subsequently, the different layers of the tri-layer structure, as well as the Ge concentration in the middle layer, were varied to study their influence on the formation and charge storage properties of the Ge nanocrystals. Finally, a study of the formation and ripening of Ge nanocrystals in a tri-layer structure under constant electron irradiation was carried out using in-situ transmission electron microscopy (TEM).