Plasma-Enhanced Storage Capability of SONOS Flash Memory

High-kappa thin film is a candidate material for the charge storage layer of non-volatile flash memory. This material can achieve faster programming speeds and better charge-retention performance. This paper reports the fabrication of a Co(x)Hf(y)Si(z)Ohigh-kappa thin film formed by using a sol-gel technique and low-temperature annealing. The proposed fabrication method involves using oxygen plasma treatment to passivate the surface of the high-kappa film and maintain low-temperature formation with high quality. The X-ray analysis presented in this study showed that the CoxHfySizO high-kappa film formed metal-rich cobalt and hafnium silicate after oxygen plasma treatment, thus improving the performance of the CoxHfySizO high-kappa memory by creating more trapping sites. This plasma treatment also improves the memory window from 1.92 to 2.16 V. The retention can decrease to 13% at a 10(6) s measurement, and the memory narrowing for the plasma-treated CoxHfySizO high-kappa memory is 21% after 10(6) program and erase cycles. The sol-gel method resulting CoxHfySizO high-kappa square flash memories show that oxygen plasma treatment improves the memory performance in retention and endurance.