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We have successfully fabricated a novel 3-D vertically stacked complementary metal-oxide-semiconductor hybrid inverter using a lower p-type poly-Si thin-film transistor (TFT) and an upper n-type amorphous Ga-In-Zn-O (a-GIZO) TFT. The device was fabricated step by step, starting from the fabrication of the lower poly-Si TFT via a high-temperature process to the fabrication of the upper a-GIZO TFT via a low-temperature process; this was done to prevent damage to the TFTs and to optimize their characteristics. The entire process was further simplified by the coplane gate structure that allows successive formation of the a-GIZO TFT on the poly-Si TFT. The transfer characteristics show clear inverter actions, indicating high performances of the TFTs.

We extracted the effective channel length and parasitic series resistance in a-IGZO inverted-staggered etch-stop (ES) TFTs. When there is an overlap between the drain or source electrode and the FET channel, the resistance of the channel underneath the overlapping regions is very low compared with other channel region resistance. As a result, the effective channel length is smaller than the physical length. The aforementioned definition of effective channel length in terms of device geometric parameters seems to be specific for ES a-IGZO TFTs.

This letter examines the effect of the gate dielectric material on the light-induced bias-temperature instability of an In-Ga-Zn-O (IGZO) thin-film transistor (TFT). After applying positive and negative bias stresses, the SiNx-gated TFT exhibited inferior stability to the SiO2-gated TFT, which was explained by the charge trapping mechanism. However, light illumination under a negative bias stress accelerated the negative displacement of the threshold voltage (Vth) of the SiNx-gated IGZO TFT compared to that of the SiO2-gated TFT. This was attributed to the injection of photocreated hole carriers into the underlying gate dielectric bulk region as well as the hole trapping at the gate/channel interface.

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/Vmiddots, subthreshold slope of 0.34 V/dec, threshold voltage of -1.67 V, and off-current of 6.6times10-14 A/mum. The 5.6-in panel had 160 times RGB times 350 pixels, each of which had a pixel circuit of two TFTs and one capacitor