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Short channel device performance of deep-submicron gate length oxide thin film transistor (TFT) with amorphous InGaZnO (a-IGZO) active semiconductor is presented. Remarkable electrical properties of short channel oxide TFT were achieved utilizing crucial structure and material optimization such as self aligned gate structure with homo junction, multi-channel with rounded corners, and high-κ gate dielectric. It was found that various device performance parameters of short channel-oxide TFTs were significantly influenced by materials, processes, and structural geometry, which should be more carefully designed. [ABSTRACT FROM AUTHOR]

The electron conduction mechanism in the above-threshold regime in amorphous oxide semiconductor thin film transistors is shown to be controlled by percolation and trap-limited conduction. The band tail state slope controls the field effect mobility, while the average spatial coherence length and potential fluctuation control percolation conduction. In these limits, the field effect mobility is found to follow a power law, from which a universal mobility versus carrier concentration dependence is extracted. [ABSTRACT FROM AUTHOR]

Electrical bias and light stressing followed by natural recovery of amorphous hafnium-indium-zinc-oxide (HIZO) thin film transistors with a silicon oxide/nitride dielectric stack reveals defect density changes, charge trapping and persistent photoconductivity (PPC). In the absence of light, the polarity of bias stress controls the magnitude and direction of the threshold voltage shift (ΔVT), while under light stress, VT consistently shifts negatively. In all cases, there was no significant change in field-effect mobility. Light stress gives rise to a PPC with wavelength-dependent recovery on time scale of days. We observe that the PPC becomes more pronounced at shorter wavelengths. [ABSTRACT FROM AUTHOR]

Abstract-The source/drain region of amorphous GaInZnO thin-film transistor with self-aligned top-gate structure was defined by simple NH[sub3] plasma treatment instead of complicated processes, such as ion implantation and activation. When the source/drain region of active layer was exposed to NH[sub3] gas plasma, the series resistance of the transistor decreased considerably. It exhibited electrical properties, such as a field-effect mobility of 6 cm[sup2]/V s, a threshold voltage of 0.21 V, and a subthreshold swing of 0.23 V/dec. [ABSTRACT FROM AUTHOR]

We fabricated gallium-indium-zinc oxide (GIZO) thin film transistors (TFTs) having a double-gated (DG) structure and studied the back gate effect on device performance. DG GIZO TFTs showed better threshold voltage (Vth), swing factor (S), and on/off current than those with a single gate. With the variation in back gate bias, the device performance significantly changes due to the modification of field distribution near the GIZO channel. It is believed that our DG structure is an effective way to improve the performance of GIZO oxide transistors and suppress the formation of an accumulation layer at the back surface. [ABSTRACT FROM AUTHOR]

We have demonstrated a self-aligned top-gate amorphous gallium indium zinc oxide thin film transistor (a-GIZO TFT). It had a field effect mobility of 5 cm2/V s, a threshold voltage of 0.2 V, and a subthreshold swing of 0.2 V/decade. Ar plasma was treated on the source/drain region of the a-GIZO active layer to reduce the series resistance. After Ar plasma treatment, the surface of the source/drain region was divided into In-rich and In-deficient regions. The a-GIZO TFT also had a constant sheet resistance of 1 kΩ/□ for a film thickness of over 40 nm. The interface between the source/drain Mo metal and the Ar plasma-treated a-GIZO indicated a good Ohmic contact and a contact resistivity of 50 μΩ cm2. [ABSTRACT FROM AUTHOR]

Amorphous-gallium-indium-zinc-oxide (a-GIZO) thin filmtransistors (TFTs) are fabricated without annealing, using processes and equipment for conventional a-Si:H TFTs. It has been very difficult to obtain sound TFT characteristics, because the a-GIZO active layer becomes conductive after dry etching the Mo source/drain electrode and depositing the a-SiO2 passivation layer. To prevent such damages, N2O plasma is applied to the back surface of the a-GIZO channel layer before a-SiO2 deposition. N2O plasma-treated a-GIZO TFTs exhibit excellent electrical properties: a field effect mobility of 37 cm2/V s, a threshold voltage of 0.1 V, a subthreshold swing of 0.25 V/decade, and an Ion/off ratio of 7. [ABSTRACT FROM AUTHOR]

In this letter, we investigated the effects of source/drain series resistance on amorphous gallium-indium-doped zinc-oxide (a-GIZO) thin film transistors (TFTs). A linear least square fit of a plot of the reciprocal of channel resistance versus gate voltage yields a threshold voltage of 3.5 V and a field-effect mobility of about 13.5 cm² / V · s. Furthermore, in a-GIZO TFTs, most of the current flows in the distance range of 0-0.5 µm from the channel edge and shorter than that in a-Si:H TFTs. Moreover, unlike a-Si:H TFTs, a-GIZO TFTs did not show an intersection point, because they did not contain a highly doped ohmic (n+) layer below the source/drain electrodes. [ABSTRACT FROM AUTHOR]