Silicon Nanoclusters Embedded into Oxide Host for Non-Volatile Memory Applications

Abstract

Non-volatile memory structures with embedded silicon nanoclusters were fabricated by RF magnetron sputtering approach. The capacitance-voltage characteristics of classical SiO2/Si-ncs-SiO2/SiO2 and HfO2/Si-ncs-SiO2/SiO2 structures have been compared. The specific deposition conditions and annealing treatment allowed a large memory window of about 6.8 V at a sweeping voltage of ± 6 V to be achieved. It was observed that the similar memory capacitance can be obtained for classical SiO2/Si-ncs-SiO2/SiO2 structures using multilayer charge storage node. The analysis of microstructural properties of the samples revealed that an annealing at 1000-1100°C results in the formation of crystallized silicon clusters, while the crystallization of HfO2 occurred with a tetragonal phase. It was also revealed that an annealing treatment at 950°C, at which amorphous Si clusters are formed, allowed a highest memory window to be obtained. This result indicates the benefit of low thermal budget treatment for low operating voltage non-volatile memory devices.