The Research Of Process And Charge Storage Of Nc-Si-based Non-volatile Memory

With the continuous development of the semiconductor IC (integrated circuit), the traditional Flash memory has suffered a bottleneck. Nanocrystals floating gate memory is attracting more and more attention due to its advantages of discrete charge storage. And a new type of resistance memory (RRAM) based on different mechanisms is becoming a hot research field of memory because of its high speed for reading and programming as well as its fabrication process compatibility with the current CMOS technology. How to improve the performance of the memory by using modern semiconductor technology is being a important project of the scientific and industry community.In this article, we have firstly investigated RIE technology to etch poly silicon with Al as a mask for nano-silicon floating gate memory structure MOS structure. And we obtained the novel conditions for etching poly silicon and successfully fabricated isolated poly-Si/Si3N4/nc-Si/SiO2MOS unit. In order to improve the electrical properties of nc-Si RRAM, we adopted nanosphere with RIE technology to get nc-Si array to restrict the space distribution of silicon quantum dots. Based on this, we use the lithography process with high resolution to reduce the top electrode area to realize the limitations of the spatial distribution of electric fields, which is benefit to optimize the electric properties of nc-Si RRAM. We found that with the electrode area becoming smaller, the electric performance of nc-Si RRAM is improved.After successfully preparing isolated poly-Si/Si3N4/nc-Si/SiO2MOS structural units, C-V and G/ω-V of this structure were measured. We calculated the density of nc-Si based on the C-V curve and analyzed the role of nc-Si during the charge storage. The frequency dependent C-V spectra and G/co-V curves were observed from isolated poly-Si/Si3N4/nc-Si/SiO2MOS structural units. The same change amplitude of frequency dependent C-V spectra and G/ω-V curves proved that both nc-Si and the interface between nc-Si and Si3N4have contributed to the charge storage.