Full-Swing Clock Generating Circuits on Plastic Using a-IGZO Dual-Gate TFTs With Pseudo-CMOS and Bootstrapping

• Published in: IEEE electron device letters Vol. 37; no. 7; pp. 882 - 885
• Main Authors: Yuanfeng Chen, Di Geng, Tengda Lin, Mativenga, Mallory, Jin Jang
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.07.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: a-IGZO; Capacitors; Clocks; Inverters; Logic gates; Optical buffering; Plastics; pseudo-CMOS; ring oscillator; TFT; Thin film transistors; TFT; pseudo-CMOS; a-IGZO; ring oscillator
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2016.2571321

As clock signals are usually supplied by external rigid ICs, they may limit mechanical flexibility of devices fabricated on plastic. Reported in this letter is a full-swing clock generating circuit that is integrated on a plastic substrate. The clock signal is generated by a 13-stages ring oscillator (RO), which is implemented by n-type-only dual-gate amorphous-indium-gallium-zinc-oxide thin-film transistors. By combining bootstrapping and pseudo-CMOS inverting, an output peak-peak voltage (V p-p ) that reaches the supply voltage (V DD ) and a high speed, reaching an output frequency of 360 kHz, are achieved. In addition, a phase modulating capacitor is implemented in the RO to increase the high voltage level holding time and the addition of a buffer in the circuit is also studied for the achievement of two antiphase outputs.