Low voltage thin film transistors based on solution-processed In2O3:W. A remarkably stable semiconductor under negative and positive bias stress

Abstract

We have investigated solution-processed tungsten-doped crystalline indium oxide (In2O3:W) as a function of the W content and their implementation in TFTs also employing spray coated Y2O3 gate dielectrics, and gold source and drain contacts. We showed that tungsten doping practically has no effect on the optical band gap whereas it shifts up the Urbach tail energy of In2O3:W films. The TFT performance employing In2O3:W channels also seems to decline at high tungsten concentration. Negative and positive bias stress under (dark) ambient conditions of TFTs employing In2O3:W(0.1 at%) showed remarkable improvement in their stability characteristics compared to the un-doped ones. This is evidenced by significantly smaller changes of the threshold voltage and subthreshold swing with insignificant change of the electron mobility that was practically unaffected under negative bias voltage. The negative bias stress results were interpreted in terms of the higher W-O bond dissociation energy compared a)

Deep-UV-Enhanced Approach for Low-Temperature Solution Processing of IZO Transistors with High-k AlOx/YAlOx Dielectric

“…Similarly, negative bias stress was evaluated by applying a voltage of −3 V under dark condition. The application of constant positive voltage for 10 3 s in air ambient condition resulted in a positive shift, consistent with the screening effect caused by the trapped charges in the insulator . The threshold voltage shift under negative gate bias stress after 10 3 s shows a reduced shift in the negative direction, which is frequently reported for n-type TFTs when subjected to this kind of stress in dark conditions .…”

“…The application of constant positive voltage for 10 3 s in air ambient condition resulted in a positive shift, consistent with the screening effect caused by the trapped charges in the insulator. 55 The threshold voltage shift under negative gate bias stress after 3 s shows a reduced shift in the negative direction, which is frequently reported for n-type TFTs when subjected to this kind of stress in dark conditions. 56 To understand how the stability could be influenced by the IZO curing, TFTs realized using different thermal budgets (minimal = 5 min DUV + 5 min at 200 °C, medium = 20 min DUV + 60 min at 200 °C, and high = 45 min DUV + 60 min at 200 °C) were evaluated.…”

Solution-processed thin film transistors incorporating YSZ gate dielectrics processed at 400 °C

“…shows the band gap versus the static dielectric constant of solution-processed gate dielectric films along with a large number of dielectric films deposited using vacuum-based techniques, [8,[78][79][80][81][82][83][84] demonstrating the attractive positioning in terms of band gap and dielectric constant of our YSZ. Also, as shown in Figure 5c, a minimum leakage current density for the highest dielectric constant is ~0.3 nA/cm 2 at an electric field of 2 MV/cm further confirms the deposition of YSZ films of superior high dielectric strength and dielectric constant compared to that of other dielectrics deposited from solutions [8,25,79,81,[84][85][86][87][88][89][90] .…”

“…[97] Next, the performance of the YSZ as a gate dielectric in bottom-gate top-contact thin films transistors was explored. The In2O3 semiconducting channel layer was previously characterized independently and found to be the cubic phase with lattice constant a of 10.0949 Å and band gap of 3.58 eV [80] (Figure S4).…”

Light-Stimulated Artificial Synapse with Memory and Learning Functions by Utilizing an Aqueous Solution-Processed In2O3/AlLiO Thin-Film Transistor

“…Therefore, considering the prospect of industrialization and its advantages, metal oxide solid electrolytes are required to play a very important role in the development of light-stimulated neural computing systems. Among metal oxides, indium oxide, as an indirect band gap n-type semiconductor, has a wide band gap (3.6–3.75 eV), excellent optical transmittance (visible spectrum), and high mobility at room temperature (about 160 cm 2 /Vs), , and it is a promising candidate for the development of optoelectronic devices.…”