Enhanced charge storage characteristics of nickel nanocrystals embedded flash memory structures

Abstract

Nickel nanocrystals (NCs) embedded flash memory structure with SiO2 tunnelling and pulsed laser deposition grown Al2O3 blocking oxide is reported here. The post-deposition thermal annealing of an ultrathin (approximate to 5nm) nickel film evaporated on thermally grown SiO2 tunnelling barrier has been performed to form the nickel NCs. The formation of tiny nickel NCs is confirmed from the high-resolution transmission electron microscope micrographs. The electrical capacitancevoltage (CV) characteristics of the optimised 1000 degrees C, 5min annealed sample shows a large memory window of 20V at +/- 20V sweeping voltage. The charge storage properties are found to be significantly improved as compared to control samples. The frequency dependent CV measurements indicate the dominant charge trapping in Ni NCs, making the memory structure attractive for use in future nanoscale high-performance applications.