Search Results (3)

Here, we report the high-performance amorphous gallium indium tin oxide (a-IGTO) thin-film transistor (TFT) with zirconium aluminum oxide (ZAO) gate insulator by spray pyrolysis. The Ga ratio in the IGTO precursor solution varied up to 20%. The spray pyrolyzed a-IGTO with a high-k ZAO gate insulator (GI) exhibits the field-effect mobility (μ_FE) of 16 cm²V⁻¹s⁻¹, threshold voltage (V_TH) of −0.45 V subthreshold swing (SS) of 133 mV/dec., and ON/OFF current ratio of ~10⁸. The optimal a-IGTO TFT shows excellent stability under positive-bias-temperature stress (PBTS) with a small ΔV_TH shift of 0.35 V. The enhancements are due to the high film quality and fewer interfacial traps at the a-IGTO/ZAO interface. Therefore, the spray pyrolyzed a-IGTO TFT can be a promising candidate for flexible TFT in the next-generation display. Full article

We examined the effects of aluminum (Al) capping layer thickness on the electrical performance and stability of high-mobility indium–gallium–tin oxide (IGTO) thin-film transistors (TFTs). The Al capping layers with thicknesses (t_Als) of 3, 5, and 8 nm were deposited, respectively, on top of the IGTO thin film by electron beam evaporation, and the IGTO TFTs without and with Al capping layers were subjected to thermal annealing at 200 °C for 1 h in ambient air. Among the IGTO TFTs without and with Al capping layers, the TFT with a 3 nm thick Al capping layer exhibited excellent electrical performance (field-effect mobility: 26.4 cm²/V s, subthreshold swing: 0.20 V/dec, and threshold voltage: −1.7 V) and higher electrical stability under positive and negative bias illumination stresses than other TFTs. To elucidate the physical mechanism responsible for the observed phenomenon, we compared the O1s spectra of the IGTO thin films without and with Al capping layers using X-ray photoelectron spectroscopy analyses. From the characterization results, it was observed that the weakly bonded oxygen-related components decreased from 25.0 to 10.0%, whereas the oxygen-deficient portion was maintained at 24.4% after the formation of the 3 nm thick Al capping layer. In contrast, a significant increase in the oxygen-deficient portion was observed after the formation of the Al capping layers having t_Al values greater than 3 nm. These results imply that the thicker Al capping layer has a stronger gathering power for the oxygen species, and that 3 nm is the optimum thickness of the Al capping layer, which can selectively remove the weakly bonded oxygen species acting as subgap tail states within the IGTO. The results of this study thus demonstrate that the formation of an Al capping layer with the optimal thickness is a practical and useful method to enhance the electrical performance and stability of high-mobility IGTO TFTs. Full article

Inkjet-printed top-gate metal oxide (MO) thin-film transistors (TFTs) with InGaSnO semiconductor layer and carbon-free aqueous gate dielectric ink are demonstrated. It is found that the InGaO semiconductor layer without Sn doping is seriously damaged after printing aqueous gate dielectric ink onto it. By doping Sn into InGaO, the acid resistance is enhanced. As a result, the printed InGaSnO semiconductor layer is almost not affected during printing the following gate dielectric layer. The TFTs based on the InGaSnO semiconductor layer exhibit higher mobility, less hysteresis, and better stability compared to those based on InGaO semiconductor layer. To the best of our knowledge, it is for the first time to investigate the interface chemical corrosivity of inkjet-printed MO-TFTs. It paves a way to overcome the solvent etching problems for the printed TFTs. Full article