Stable Logic Operation of Fiber-Based Single-Walled Carbon Nanotube Transistor Circuits Toward Thread-Like CMOS Circuitry.

Jae Heo,Taehoon Kim,In-Soo Kim,Daesik Kim,Yongtaek Hong,Kyung-Tae Kim,Seok-Gyu Ban,Sung Park,Yoon-Jeong Kim

doi:10.3390/ma11101878

Abstract

A fiber-based single-walled carbon nanotube (SWCNT) thin-film-transistor (TFT) has been proposed. We designed complementary SWCNT TFT circuit based on SPICE simulations, with device parameters extracted from the fabricated fiber-based SWCNT TFTs, such as threshold voltage, contact resistance, and off-/gate-leakage current. We fabricated the SWCNTs CMOS inverter circuits using the selective passivation and n-doping processes on a fiber substrate. By comparing the simulation and experimental results, we could enhance the circuit’s performance by tuning the threshold voltage between p-type and n-type TFTs, reducing the source/drain contact resistance and off current level, and maintaining a low output capacitance of the TFTs. Importantly, it was found that the voltage gain, output swing range, and frequency response of the fiber-based inverter circuits can be dramatically improved.

Highlights

Portable, wearable, patchable, and implantable systems have required high performance and flexible electronics
We optimized the cuit design using an Automatic Integrated Circuit Modeling (AIM)-SPICE simulation with TFT device parameters and CMOS inverte erational characteristics
For the rail-to-rail operations with high gain of logic inverte between the unpatterned gate electrode and the source/drain electrodes, and the bottom contact device configuration can lead to a large Ioff, including a high gate leakage and high source/drain contact resistance (Rc) (300 kΩ), respectively, which is inevitable because of the nature of the CMOS

Summary

Introduction

Portable, wearable, patchable, and implantable systems have required high performance and flexible electronics. Flexible electronics, such as flexible printed circuit board (PCB)-based and polydimethylsiloxane (PDMS)-based electronics, are used for a variety of wearable electronic applications [1,2,3]. Electronic textiles (e-textiles) have been highlighted as the generation of smart and wearable electronics for human-friendly applications, because they are light weight, have deformability in movement, and have a wide range of applications within various fields [4,5]. A high degree of mechanical flexibility/durability and washability must be achieved for long-term use. High performance active devices, such as thin-film-transistors (TFTs) and light-emitting diodes (LEDs), should be developed for electronic circuit operations including fast-switching, amplification, and digital logics

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Conclusion