Flash memory based on solution processed hafnium dioxide charge trapping layer

Hafnium dioxide (HfO₂) film prepared by the sol-gel technique has been used as a charge trapping layer in organic flash memory. The thickness, crystallinity and morphology of HfO₂ fabricated under various conditions were investigated. X-ray diffraction (XRD) patterns indicated the formation of monoclinic HfO₂ crystals with increasing annealing temperature. Atomic force microscopy (AFM) images showed relatively smooth films of HfO₂ growth. The annealing temperature-dependent effects on the memory window as well as data retention properties have been discussed. A large memory window and long data retention time have been achieved for the pentacene-based flash memory. The results demonstrate that solution processed HfO₂ film could be a promising candidate as a charge trapping layer in printable flash memory.