A Depletion-Mode a-IGZO TFT Shift Register With a Single Low-Voltage-Level Power Signal

We proposed and fabricated a new depletion-mode amorphous indium-gallium-zinc-oxide thin-film-transistor (a-IGZO TFT) shift register. Although only one low-voltage-level power signal (VGL) rather than widely used two ones was employed, the depletion-mode a-IGZO TFTs in the proposed shift register were turned off completely due to a series-connected two-transistor structure. The proposed shift register exhibited successfully a high-voltage output pulse. The power consumption of the shift register with ten stages is 1.67 mW at the high-voltage-level power signal of 20 V, the VGL of -5 V, and the clock frequency of 13.9 kHz.