AC Performance of Flexible Transparent InGaZnO Thin-Film Transistors and Circuits

Abstract

Transparent transistors are mainly investigated in view of their integration in displays and their employment in wearable electronics where the integration of flexible and imperceptible systems is an important requirement. Here, the fabrication and ac performance of flexible InGaZnO thin-film transistors (TFTs) and circuits are presented to evaluate their suitability for analog sensor conditioning applications. Functional oxides are employed to guarantee the transparency of the device, while their fabrication processes are suitable to directly realize electronics on a flexible polyimide substrate. The TFTs show stateof-the-art performance with a field-effect mobility μ eff = 19.39 cm 2 V −1 s −1 and functionality while bent to radii as low as 5 mm. Reliable scattering parameters measurements confirm transit frequencies as high as f t ≈ 7.84 MHz. Simultaneously, nMOS ring oscillators (ROs) show functionality at supply voltage V DD ranging from 1.75 to 12.25 V with a maximum oscillation frequency f osc = 132.9 kHz. Finally, common-source amplifiers (CSAs) exhibit the voltage gains up to 10.7 dB, the cutoff frequencies up to 10.8 kHz, and a power consumption down to 4.4 μW.

Substrate‐Free Transfer of Large‐Area Ultra‐Thin Electronics

“…[ 1 ] Differently from rigid electronics, thin‐film and flexible electronics are able to maintain their functional characteristics even if they are not in their original mechanical state. [ 2,3 ] They have made possible new applications [ 4 ] on deformable optoelectronics, [ 5 ] transient, [ 6 ] curvilinear electronics, [ 7 ] wearable devices for health diagnostics and artificial intelligence, [ 8 ] power source devices, [ 9 ] transparent electronics, [ 10 ] and sensors. [ 11,12 ]…”

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to maintain their functional characteristics even if they are not in their original mechanical state. [2,3] They have made possible new applications [4] on deformable optoelectronics, [5] transient, [6] curvilinear electronics, [7] wearable devices for health diagnostics and artificial intelligence, [8] power source devices, [9] transparent electronics, [10] and sensors. [11,12] Traditionally, thin-film electronics and sensors are fabricated through a lithography process directly carried out on polymeric substrates, like polyimide (PI), polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), and polyethylene terephthalate (PET), as they endow the devices with mechanical flexibility and stable electronics performance.

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Temperature Dependent Anomalous Threshold Voltage Modulation of a-IGZO TFT by Incorporating Variant Gate Stresses

“…The top gate supports to tailored the V th to enhance the performance of device. 6,35 We have performed a PBS test for a channel width of 1080 nm with a 1020 nm channel length under a constant V BG = 4 V stress for 1000 s duration. Figure 8a shows the initial (0 s) transfer curves of a-IGZO-TFTs for variant TG voltages.…”

Channel Nanoscaling of InGaZnO TFTs and Circuits via Focused Ion Beam

“…Successively, a 45 nm/thick IGZO semiconducting layer was deposited by RF sputtering at room temperature. Thicker oxide layers compared to the conventional thickness used for our devices were used to prevent excessive contamination of the semiconductor and damage of both the active and dielectric layers during the FIB milling process. , The patterning of the semiconductor and the insulating layer was performed by UV lithography and wet etching processes. Finally, the source/drain metal contacts consisting of a 10 nm-thick Ti adhesion layer and a 75 nm-thick Au film were deposited by e-beam evaporation and structured by lift-off.…”