Stress-Released Amorphous Oxide/Carbon Nanotube CMOS Amplifier Circuits for Skin-Compatible Electronics

Abstract

Recently, there has been a great interest for realizing flexible, cheap, smart, and disposable bioelectronics and implantable electronic systems that can collect various types of in vivo biological signals from the body. In these cases, highly flexible amplifier circuits are often demanded as a basic building block for the realization of the bioelectronic systems with high signal-to-noise ratio. Here, we report highly flexible amorphous indium–gallium–zinc oxide (a-IGZO)/single-walled carbon nanotube (SWCNT) thin-film-transistor-based hybrid-type complementary metal oxide semiconductor (CMOS) amplifiers by introducing a stress-diffusive mesa-island structure. The hybrid amplifier showed stable operation under extremely stressed conditions (bending radius of 125 μm, 10000 cycles) without significant degradation, exhibiting a maximum gain of ∼21.6 dB at 0.1–5 kHz with a gain loss of −9.9 dB/dec over 10 kHz. Additionally, to ensure the viability of the developed stress-released CMOS circuits, we provided a circuit level physical modeling and synthetic analysis using structural and electrical characterizations along with multidomain finite-element analysis (FEA) and AIM-Spice simulation, verifying the acts of the materials and device architecture as a way of highly reliable and outperforming skin-compatible amplifier circuits. The results reported here imply that further neutral layer generation and its intermediate location can be controlled by device architectures and component materials, offering extremely reliable and high performance CMOS amplifier circuits for large-scaled skin-compatible on-chip applications.