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A number of reports have demonstrated the feasibility of oxide thin film transistors (TFTs) replacing silicon-based technology in active-matrix liquid-crystal displays (AMLCDs) and active-matrix organic light emitting diodes (AMOLEDs). Among oxide materials, zinc tin oxide (ZTO) is being tipped off as an appropriate alternative for amorphous-silicon. ZTO tops its adversaries because it has a robust amorphous phase compared to ZnO and has a more simple composition compared to InGaZnO. Although ZTO TFTs showed their good performance, the stability issues of these devices have not yet been addressed. Because TFTs are used in display technology, the effect of light on their electrical performance is a vital matter that should be considered. Therefore, in this work, the effect of light illumination on the negative bias temperature instability (NBTI) of ZTO TFTs is investigated.

A new ferroelectric memory array on a glass substrate has been developed using In-Ga-Zn-O (IGZO) thin-film transistors (TFTs). Each memory cell is composed of two normal IGZO TFTs and a ferroelectric TFT (FeTFT). Poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] is employed as the gate dielectric layer of the FeTFT. All the fabrication processes were performed below 200°C. The fabricated memory successfully demonstrated disturb-free write/readout operation. The current ratio between the “1” and “0” states is about 104.

This paper reports the fabrication and characterization of metal-insulator-semiconductor (MIS) capacitors using a ZnO semiconducting layer and Al 2 O 3 insulating layer deposited by plasma-enhanced atomic layer and thermal atomic layer deposition, respectively. The sample stack structure is Al 2 O3 / ZnO/ITO. The effects of the ZnO deposition conditions, such as plasma power, film thickness, and oxygen flow rate, on the electrical characteristics of the MIS capacitors were investigated. The thicknesses of the ZnO and Al 2 O 3 layers were changed independently in order to examine the influence of full depletion of carriers on the capacitance-voltage (C-V) characteristics. It was found that the electrical properties of the ZnO thin films changed according to their thickness. This was attributed to a chemical interaction with the under-indium-tin-oxide (ITO) layers during the long growth time (over 2 h), which made it difficult to determine the semiconductor parameters, such as the carrier density. During the process of Al 2 O 3 film deposition, an interfacial layer was grown between the ZnO and Al 2 O 3 films. This interfacial layer deteriorated the C-V characteristics of the MIS capacitors because of the interface state increment. It was found that there was a certain range of ZnO and Al 2 O 3 thicknesses where the optimal properties were achieved.