SONOS-type flash memory using an HfO₂as a charge trapping layer deposited by the sol-gel spin-coating method

In this letter, the authors fabricate the silicon-oxide-nitride-oxide- silicon (SONOS)-like memory using an HfO₂as charge trapping layer deposited by a very simple sol-gel spin-coating method and 900°C 1-min rapid thermal annealing. They examine the quality of sol-gel HfO₂ charge trapping layer by X-ray photoemission spectroscopy, Id-V g, charge retention, and endurance. The threshold voltage shift is 1.2 V for the sol-gel HfO₂ trapping layer. The sol-gel HfO₂ film can form a deep trap layer to trap electrons for the SONOS-like memory. Therefore, the sol-gel device exhibits the long charge retention time and good endurance performance. The charge retention time is 10⁴ s with only 6% charge loss and long endurance program/erase cycles up to 10⁵.