Amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistor (TFT) nonvolatile memory devices with an IGZO charge storage layer were evaluated for the first time for multi-level cell memory applications.The pristine memory device was defined as original state, which can be switched to programmed state after a positive gate voltage pulse (for example, 12 V for 10 ms), and to erased state after a negative gate voltage pulse (for example,-15 V for 10 ms).The devices demonstrated superior electrical programmable-erasable characteristics.A memory window of 2.4 V between original state and programmed state was maintained after 100 program/restore cycles.A memory window of 2.66 V was observed between original state and erased state after 100 erase/restore cycles.The memory windows relative to original state are equal to 1.91 V and i.30 V for programmed state and erased state,respectively for a retention time of 105 s.