Read-out modulation scheme for the display driving circuits composed of nonvolatile ferroelectric memory and oxide-semiconductor thin-film transistors for low-power consumption

New circuit architecture composed of nonvolatile memory thin-film transistors (M-TFTs) and oxide-semiconductor TFTs (Ox-TFTs) has been proposed to realize low-power consumption and compact size for dynamic driving circuit applications. In order to compensate the slow operation speed of the nonvolatile M-TFTs in the dynamic driving circuits, we proposed the read-out modulation (ROM) scheme. The device operation characteristics of the M-TFTs were confirmed under various specified conditions to effectively apply the ROM, in which a top-gate structure was fabricated to be ferroelectric poly(vinylidene fluoride-trifluoroethylene) gate insulator/Al₂O₃/In-Ga-ZnO active layers. Full fabrication processes for the M-TFTs were optimized, so that they can be integrated with Ox-TFTs on the same glass substrate. The memory device characteristics, including the current ratios between ON- and OFF-programmed drain current (I_D) values (I_p-ON/I_p-OFF) before and after the ROM, drain-bias dependence of the I_p-ON/I_p-OFF, and the program I_D scalability, were confirmed for the fabricated M-TFT. These results suggest the feasibility of a low-power display driver circuit embedded with the nonvolatile M-TFTs.