Improved performances of metal-oxide-nitride-oxide-silicon memory with HfTiON as charge-trapping layer

The properties of HfTiON as charge-trapping layer of metal-oxide-nitride-oxide-silicon memory are investigated, and effects of different Hf/Ti ratios in HfTiON films on the physical and electrical characteristics are analyzed. It is found that the higher the Ti content, the higher is the charge-trapping efficiency, thus, larger memory window and higher program/erase speeds. However, excessive Ti can diffuse to the HfTiON/SiO2 interface and cause the formation of a Ti-silicate interlayer, which deteriorates the retention of data. Experimental results indicate that the device with a Hf/Ti ratio of ∼1:1 can give a good trade-off between performance and reliability.