Since the report by Nomura et al. [1] thin film transistors (TFTs) based on amorphous oxide semiconductors (AOSs) have emerged as a promising technology, particularly for active-matrix TFT-based backplanes, due to their superior electrical performance when compared with conventional amorphous silicon and polycrystalline silicon TFTs. Among the various AOSs, amorphous indiumgallium-zinc-oxide (a-IGZO) TFTs have high field-effect mobilities exceeding that of a-Si by a factor of 10 2 , a small subthreshold swing, good uniformity attributed to the amorphous structure, a low off current, good stability under electrical stress, and can be processed at low temperatures. Several research groups have already presented a-IGZO based working devices with remarkable electrical and optical properties. We have recently demonstrated high performance a-IGZO TFTs which exhibited a field effect mobility µ FE of 19.4 cm 2 /Vs, a subthreshold swing S of 0.5 V/decade, and a ratio of on and off current I ON /I OFF of 10 8 , respectively [2].Despite recent successes, some outstanding issues related to the a-IGZO TFT electrical performance still remain to be resolved, such as obtaining good electrical contact between source/drain (S/D) electrodes. A previous report [3] on contact resistance of candidate metal electrodes and a-IGZO showed the trend that the contact resistance decreases with the work function of the metallic electrode. High work function electrodes showed Schottky contacts, while reactive electrodes did ohmic contact. However, using reactive metals for an electrical contact require a high reproducibility of the process.We focus here on an investigation of Cu electrodes to obtain good ohmic characteristics in a-IGZO based TFTs. Specifically, we discuss the S/D series resistances and their effects on the TFT performance. The TFT S/D series resistance, the intrinsic field effect mobility µ FE-i , transfer length L T , and effective contact resistance R C-eff were extracted by the well-known transmission line method (TLM) using a series of TFTs with different channel lengths.The bottom gate type a-IGZO TFTs with staggered structure were prepared on heavily doped n-type silicon substrates having a LPCVD SiN x layer of 100 nm. Thin films of a-IGZO (80 nm thick) were deposited using DC magnetron sputtering with sintered InGaZnO 4 (99.999% purity) as the target material. Sputtering was performed at room temperature in an argon atmosphere with an oxygen partial pressure of 4%. A 4 inch diameter ceramic target, This paper focuses on the viability of low-resistivity electrode material (Cu) for source/drain electrodes in thin film transistors (TFTs). The effective resistances between Cu source/drain electrodes and amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors were examined. Intrinsic TFT parameters were extracted by the transmission line method (TLM) using a series of TFTs with different channel lengths measured at a low source/drain voltage. The TFTs fabricated with Cu source/drain electrodes showed good transfe...

Plasma enhanced atomic layer deposition (PEALD) of titanium dioxide thin films was conducted using Tetrakis dimethylamino titanium (TDMATi) and an oxygen plasma on a polyethersulfon (PES) substrate at a deposition temperature of 90 degrees C. The effects of the induced plasma power on passivation properties were investigated according to film thickness. The growth rate of the titanium dioxide film was 0.8 A/cycle, and the water vapor transmission rate (WTVR) for a 80 nm titanium dioxide film was 0.023 g/m2 day. The passivation performance of the titanium dioxide film was investigated using an organic light-emitting diode (OLED). The coated OLED lifetime was 90 h, 15 times longer than that of an uncoated sample.