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A spike-timing-dependent plasticity (STDP) device with a Ga-Sn-O (GTO) conductance change layer deposited by a mist-CVD method has been developed. First, the memristive characteristic is analyzed. Next, based on it, spike waveforms are determined. Finally, the STDP characteristic is successfully confirmed. This is an original report on the realization of an STDP characteristic using a thin film deposited by the mist-CVD method, which is achieved by the GTO properties and a well-designed clear methodology to realize a STDP characteristic from a memristive characteristic. [ABSTRACT FROM AUTHOR]

IGZO TFTs are analyzed, and GTO devices are introduced as rare metal free devices. GTO TFTs are made by simple sputtering, and the performance is excellent, such as, mobility=34.6 cm2/Vs, good stability, etc. We propose applications of IGZO and GTO devices to not only FPDs but also thermoelectric and neuromorphic devices. [ABSTRACT FROM AUTHOR]

We have developed neuron MOS devices using TFTs. They possess floating and multiple input gate terminals capacitively connected. We evaluated neuron MOS transistors, a neuron inverter, which can be a variable threshold voltage inverter, and an almighty logic circuit. The neuron MOS devices have great potential for artificial neural networks. [ABSTRACT FROM AUTHOR]

We have analyzed the Hall effect in a thin-film transistor. First, we investigated the dependence of the Hall voltage on the gate voltage. In the subthreshold region, a relatively large Hall voltage is generated regardless of the magnetic field. This is due to the zigzag path of the current flow. In the saturation region, as the gate voltage increases, the Hall voltage also increases, which is dependent on the magnetic field, and in the linear region, it is saturated. Next, we investigated the dependence on the drain voltage. In the linear region, as the drain voltage increases, the Hall voltage also increases, and in the saturation region, it is saturated again. These behaviors can be explained by the electric field in the channel layer calculated using device simulation. [ABSTRACT FROM PUBLISHER]

Abstract: Undoped ZnO films were deposited by radio frequency (RF) magnetron sputtering on amorphous buffer layers such as SiO x , SiO x N y , and SiN x prepared by plasma enhanced chemical vapor deposition (PECVD) for dielectric layer in thin film transistor (TFT) application. ZnO was also deposited directly on glass and quartz substrate for comparison. It was found that continuous films were formed in the thickness up to 10nm on all buffer layers. The crystallinity of ZnO films was improved in the order on quartz>SiO x >SiO x N y >glass>SiN x according to the investigated intensities of (002) XRD peaks. The crystallite sizes of ZnO were in the order of SiO x ∼glass >SiN x . Stable XRD parameters of ZnO thin films were obtained to the thickness from 40 to 100nm grown on SiO x insulator for TFT application. Investigation of the ZnO thin films by atomic force microscope (AFM) revealed that grain size and roughness obtained on SiN x were larger than those on SiO x and glass. Hence, both nucleation and crystallinity of sputtered ZnO thin films remarkably depended on amorphous buffer layers. [Copyright &y& Elsevier]

Ion implantation experiments of Ga and Al into sputter-deposited ZnO films were carried out to control the resistivity to form n+-ZnO layers for device fabrication. The difference would be suitable for fabricating source and drain regions of ZnO thin film transistors. Improvement of ZnO crystallinity after the ion implantation was found by x-ray diffraction spectra and a thin film as shift of lattice parameter, enhancement of peak intensity, and a decrease of full width at half maximum in 2θ. The improvement of Ga-implanted ZnO was better than that of the Al-implanted ZnO throughout the experiment. Difference in sheet resistance for seven orders of magnitude between unimplanted ZnO thin film and Ga-implanted ZnO was observed with postannealing at 300 °C. The sheet resistance of the ZnO film was decreased to 3.4×102 Ω/□ with a postimplantation annealing at 450 °C. [ABSTRACT FROM AUTHOR]

Abstract: Zinc oxide (ZnO) film was deposited on a glass substrate by rf magnetron sputtering with O2/Ar as working gases. Structural properties of the films were characterized by XRD. Average crystallite size in the films was strongly dependent on both the gas flow ratio of O2/Ar and rf-power at a constant deposition pressure. During the deposition, energetic species in the plasma were in situ monitored using optical emission spectroscopy. An inverse correlation was observed between the average crystallite size and the emission intensity ratio of . Bombardment of atomic oxygen to the growing surface played an important role in determining the average crystallite size in the films. The average crystallite size could be controlled by the emission intensity ratio of . [Copyright &y& Elsevier]