An Integrated Analog Front‐End System on Flexible Substrate for the Acquisition of Bio‐Potential Signals

Abstract

The application of a versatile, low-temperature thin-film transistor (TFT) technology is presently described as the implementation on a flexible substrate of an analog front-end (AFE) system for the acquisition of bio-potential signals. The technology is based on semiconducting amorphous indium-gallium-zinc oxide (IGZO). The AFE system consists of three monolithically integrated constituent components: a bias-filter circuit with a bio-compatible low cut-off frequency of ≈1 Hz, a 4-stage differential amplifier offering a large gain-bandwidth product of ≈955 kHz, and an additional notch filter exhibiting over 30 dB suppression of the power-line noise. Respectively built using conductive IGZO electrodes with thermally induced donor agents and enhancement-mode fluorinated IGZO TFTs with exceptionally low leakage current, both capacitors and resistors with significantly reduced footprints are realized. Defined as the ratio of the gain-bandwidth product of an AFE system to its area, a record-setting figure-of-merit of ≈86 kHz mm −2 is achieved. This is about an order of magnitude larger than the < 10 kHz mm −2 of the nearest benchmark. Requiring no supplementary off-substrate signal-conditioning components and occupying an area of ≈11 mm 2 , the stand-alone AFE system is successfully applied to both electromyography and electrocardiography (ECG).

50‐4: Invited Paper: Low‐Temperature Metal‐Oxide Thin‐Film Transistor Technology and the Realization of Electronic Systems on Flexible Substrates

“…BG EMMO TFTs have been deployed to construct an AFE on a flexible substrate (8). The AFE comprises a bias-filter, a differential amplifier, and a notch filter.…”

“…In Section 3 is described the technique of fluorination to reduce the scattering of TFT parameters and to improve the reliability of a TFT against electrical stress (2). Finally in Section 4, the utility of the improved 300-℃ technology is demonstrated by the construction of a gatedriver on array (GOA) for active-matrix displays (7), an analog frontend (AFE) for acquiring bio-potential signals (8), and an artificial neural network (ANN) for neuromorphic computing (9).…”

Low-temperature metal–oxide thin-film transistor technologies for implementing flexible electronic circuits and systems

“…4(a) is the gate-level schematic, consisting of 2 inverters (INV) and 4 NOR gates, and the truth table of a 2-4 decoder with 2 inputs ( and ) and 4 outputs ( , , and ). Designed in the "pseudo-CMOS" style [20] , the TFT-level schematics and the truth tables of INV and NOR are shown respectively in Figs. 4…”

Exceptionally large fracture strength and stretchability of 2D ReS2 and ReSe2

“…Flexible and stretchable nano materials are desired in many advanced applications, such as biomedical applications, 37 thermal management layers, 38 portable nanogenerators, 39 and electronic components. [40][41][42][43] Therefore, the insights gained here will facilitate the integration of 2D Re dichalcogenides into such applications.…”