Investigation of Mechanical-Stress-Induced Electrical Failure of Oxide-Based Flexible Charge-Trap Memory Thin-Film Transistors Fabricated on Plastic Substrates

Oxide-semiconductor-based charge-trap memory thin-film transistors were analyzed in order to figure out the origins of the electrical failure under bending situations. Accurate evaluation on the transfer characteristics and visual inspection of electronic devices on plastic substrate were conducted by using modified bending jigs. Electrical failures of the devices were found to be attributed to the micro-cracks developed in inorganic barriers corresponding to the back-channel regions. Variations in threshold voltage and program speed were also observed before the final failure. These results will be of great help in designing flexible nonvolatile memory devices because there are few researches on the charge-trap mechanism affected by the mechanical stress.