A Depletion-Mode In–Ga–Zn–O Thin-Film Transistor Shift Register Embedded With a Full-Swing Level Shifter

We proposed and fabricated the shift register embedded with a full-swing level shifter employing the depletion-mode In-Ga-Zn-O thin-film transistors (IGZO TFTs). In the level shifter, two clock signals with 180° out of phase and one start signal were employed to obtain a full-swing output. Also, the depletion-mode IGZO TFTs in the shift register were successfully turned off by employing two low-voltage-level signals. The level shifter and the shift register consist of six TFTs and one capacitor, and 11 TFTs, respectively. The depletion-mode IGZO TFT shift register embedded with a level shifter exhibited a high-voltage output pulse without any distortion. The power consumption is 2.13 mW at a VGH of 20 V, a VGL1 of -10 V, and a clock frequency of 12.5 kHz.