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A thermally stable Ca-doped CuOx (CuCaOx) diffusion barrier to prevent the migration of Cu to amorphous InGaZnO (a-IGZO) was developed by reactive sputtering and subsequent annealing. Insertion of a 5-nm-thick CaCuOx between the Ca-dopedCu (CuCa) and a-IGZO channel films in the source/drain contact regions provided the resulting transistors with superior charge transport and lower trap density compared to the diffusion barrier-free CuCa/a-IGZO transistors. The fabricated a-IGZO transistors with the CuCa/CuCaOx stack contact exhibited a high mobility of 20.8 cm²/V ⋅ s and an Ion/off ratio of 108. Simultaneously, very stable behavior against the external positive/negate gate bias stress was observed for the a-IGZO thin-film transistors with the CuCa/CuCaOx stack contact. This was attributed to suppression of Cu-related acceptor-like traps due to the conformal formation of CuCaOx film with excellent barrier properties. [ABSTRACT FROM AUTHOR]

This paper examined the performance and bias stability of amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) with a self-aligned coplanar structure. The activation energy barrier responsible for the positive bias thermal stress (PBTS)-induced instability of the a-IGZO TFTs with low oxygen loadings can be attributed to the migration of cation interstitial defects. However, the IGZO TFTs with high oxygen loadings could not be explained by the existing defect model. The first-principle calculation indicates that the cation vacancy, such as VIn, with the hydrogen incorporation plays an important role in determining the PBTS-dependent degradation of the threshold voltage. [ABSTRACT FROM AUTHOR]

This brief reports a flexible active-matrix organic light-emitting diode display based on a poly-Si thin-film transistor (TFT) backplane. The p-channel poly-Si TFTs on metal foil exhibited a maximum field- effect mobility of 86.1 cm²/Vs, threshold voltage of 3.5 V, gate voltage swing of 0.8 V/dec, and the minimum off current of 10-12 A/gm at Vds = -0.1 V. A 4.1-in active-matrix backplane was fabricated with the poly-Si TFT with a conventional pixel circuit consisting of 2 TFTs and one capacitor. The scan driver circuits with PMOS were integrated on the flexible metal foil. The toy emission, organic light emitting display having a brightness of 100 cd/m². [ABSTRACT FROM AUTHOR]

We fabricated high-performance thin-film transistors (TFTs) with an amorphous-Al-Sn-Zn-In-O (a-AT-ZIO) channel deposited by cosputtering using a dual Al-Zn-O and In-Sn-O target. The fabricated AT-ZIO TFTs, which feature a bottom-gate and bottom-contact configuration, exhibited a high field-effect mobility of 31.9 cm2/V . s, an excellent subthreshold gate swing of 0.07 V/decade, and a high Ion/off ratio of > 10°, even below the process temperature of 250 °C. In addition, we demonstrated that the temperature and bias-induced stability of the bottom-gate TFT structure can significantly be improved by adopting a suitable passivation layer of atomic-layer- deposition-derived Al2O3 thin film. [ABSTRACT FROM AUTHOR]

Full-color active-matrix organic light-emitting diode panels, driven by poly-Si thin-film transistors (poly-Si TFTs), were successfully fabricated on thin metal foil substrates. The p-channel poly-Si TFTs on metal foil showed a field-effect mobility of 82.9 cm²/V · s, subthreshold slope of 0.34 V/dec, threshold voltage of -1.67 V, and OFF-current of 6.6 × 10-14 A/µm. The 5.6-in panel had 160 × RGB × 350 pixels, each of which had a pixel circuit of two TFTs and one capacitor. [ABSTRACT FROM AUTHOR]