Plasma-enhanced storage capability of SONOS flash memory

High 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_xHf_ySi_zO high 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 film and maintain low-temperature formation with high quality. The X-ray analysis presented in this study showed that the Co_xHf_ySi_zO high film formed metal-rich cobalt and hafnium silicate after oxygen plasma treatment, thus improving the performance of the Co_xHf_ySi_zO high 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 10⁶ s measurement, and the memory narrowing for the plasma-treated Co_xHf_ySi_zO high memory is 21% after 10⁶ program and erase cycles. The sol-gel method resulting Co_xHf_ySi_zO highflash memories show that oxygen plasma treatment improves the memory performance in retention and endurance.