The authors fabricate the hafnium silicate nanocrystal memory for the first time using a very simple sol-gel-spin-coating method and 900 degC 1-min rapid thermal annealing (RTA). From the TEM identification, the nanocrystals are formed as the charge trapping layer after 900 degC 1-min RTA and the size is about 5 nm. They demonstrate the composition of nanocrystal is hafnium silicate from the X-ray-photoelectron-spectroscopy analysis. They verify the electric properties in terms of program/erase (P/E) speed, charge retention, and endurance. The sol-gel device exhibits the long charge retention time of 104 s with only 6% charge loss, and good endurance performance for P/E cycles up to 105
