Low-temperature processed InGaZnO MES-FET for flexible device applications

Amorphous oxide semiconductor (AOSs) of an In-Ga-Zn-O (IGZO)1) is expected to be used as a channel material for thin-film transistors (TFTs) because the IGZO TFTs exhibit field-effect motility (μFE) of over 10 cm2/Vs and good uniformity even fabricate at room temperature. The oxide TFTs with metal-insulator-semiconductor (MIS) structure have been employed widely; however, maximum processing temperature of 300-400 °C is required to guarantee the performance and reliability of the TFTs. In contrast, metal-semiconductor field effect transistor (MES-FET) has several advantages especially for flexible devices since a Schottky gate can be formed at low temperature with AOSs. There are a few reports of AOSs based MES-FET2, 3); however, it has remained an issue to form stable and good Schottky contact on the AOSs. We reported the top-gated MES-FET with the IGZO channel, which was deposited by mist chemical vapour deposition at 350 °C, and sputtered silver oxide (AgOx) Schottky gate4). The μFE of 3.2 cm2/Vs and subthreshold swing (SS) of 356 mV/decade were achieved. However, a maximum processing temperature of the MES-FET was 350 °C, which was not suitable for flexible device applications. In this presentation, the IGZO MES-FET with AgOx Schottky gate was fabricated at a maximum processing temperature of 150 °C. We investigated the influences of deposition conditions and post-deposition annealing on electrical properties of the low-temperature processed IGZO MES-FET. Figure 1 shows a cross sectional view of the IGZO MES-FET. First, a 100 nm-thick IGZO film was deposited on glass substrate by DC magnetron sputtering without intentional substrate heating from InGaZnO (In:Ga:Zn=1:1:1 mol.%) target. Deposition pressure was kept at 1.0 Pa, while the O2 gas ratio [R(O2)=O2/(Ar+O2)] was varied at 0.66, 0.80, and 1.00%. The IGZO film was patterned into an active channel by conventional photolithography and wet etching. The IGZO channel was then annealed at 100 or 150 ºC for 1h in ambient air. A 120 nm-thick AgOx was deposited by DC reactive sputtering, and Au was deposited on the AgOx by thermal evaporation. The AgOx/Au stacked Schottky gate was patterned by lift-off. Finally, Mo source and drain electrodes was formed by lift-off. Channel width/length of the MES-FET was 100/10 μm. Figure 2 shows the (a) forward and reverse currents of the IGZO/AgOx Schottky diode and (b) on and off current of the IGZO MES-FET, as a function of the Hall carrier concentration (NHall) in the IGZO channel. The diode properties were well correlated with the NHall; however, on-current of the MES-FET depended on not only NHall but also the R[O2] of the IGZO deposition. Carrier transport mechanism of the IGZO MES-FET and control methods of electrical properties will be discussed at the conference. Please click Additional Files below to see the full abstract

THE ENERGY CONVERSION EFFICIENCY OF DRIVER SHOT IN FEMALE PROFESSIONAL AND AMATEUR GOLFERS

The purpose of this study was to evaluate the performance of driver shot from the viewpoint of the energy conversion efficiency between club head and ball at impact. Six female professional golfers and six female amateur golfers participated in this study. All subjects were instructed to hit a straight ball with their usual swing. Each subject performed ten trials. Three dimensional coordinates of reflective markers attached on a body and club landmarks were obtained using the motion capture system operating at 250 Hz. High speed camera was used to measure the movement of the club head and ball. The energy conversion efficiency was significantly different between professional and amateur golfers (

COMPARISON OF GOLF SWING PATTERNS IN SKILLED FEMALE GOLFERS AMONG THREE DIFFERENT CLUBS

The purpose of this study was to compare golf swing patterns using three different clubs among skilled golfers. Five right-handed female professional golfers used their own three clubs (driver, 5-iron, and 9-iron) to hit standard golf balls in our laboratory. 3D coordinates of body and club landmarks during the swing motions were recorded using a 3D motion capture system with operating at 250 Hz frame rates. As the results, the acceleration of club head in each club during downswing reached a maximum around about 0.08 s before impact during similar swing time, and the height of club head at the maximum acceleration showed about 55% of ratio for the body height despite differences of clubs. Skilled golfers therefore might feel as the similar patterns of golf swing even if they are swinging with different length clubs

Reducing nonideal to ideal coupling in random matrix description of chaotic scattering: Application to the time-delay problem

We write explicitly a transformation of the scattering phases reducing the problem of quantum chaotic scattering for systems with M statistically equivalent channels at nonideal coupling to that for ideal coupling. Unfolding the phases by their local density leads to universality of their local fluctuations for large M. A relation between the partial time delays and diagonal matrix elements of the Wigner-Smith matrix is revealed for ideal coupling. This helped us in deriving the joint probability distribution of partial time delays and the distribution of the Wigner time delay.Comment: 4 pages, revtex, no figures; published versio

AC resistivity of d-wave ceramic superconductors

We model d-wave ceramic superconductors with a three-dimensional lattice of randomly distributed $\pi$ Josephson junctions with finite self-inductance. The linear and nonlinear ac resistivity of the d-wave ceramic superconductors is obtained as function of temperature by solving the corresponding Langevin dynamical equations. We find that the linear ac resistivity remains finite at the temperature $T_p$ where the third harmonics of resistivity has a peak. The current amplitude dependence of the nonlinear resistivity at the peak position is found to be a power law. These results agree qualitatively with experiments. We also show that the peak of the nonlinear resistivity is related to the onset of the paramagnetic Meissner effect which occurs at the crossover temperature $T_p$, which is above the chiral glass transition temperature $T_{cg}$.Comment: 7 eps figures, Phys. Rev. B (in press

Dysbindin Regulates the Transcriptional Level of Myristoylated Alanine-Rich Protein Kinase C Substrate via the Interaction with NF-YB in Mice Brain

BACKGROUND: An accumulating body of evidence suggests that Dtnbp1 (Dysbindin) is a key susceptibility gene for schizophrenia. Using the yeast-two-hybrid screening system, we examined the candidate proteins interacting with Dysbindin and revealed one of these candidates to be the transcription factor NF-YB. METHODS: We employed an immunoprecipitation (IP) assay to demonstrate the Dysbindin-NF-YB interaction. DNA chips were used to screen for altered expression of genes in cells in which Dysbindin or NF-YB was down regulated, while Chromatin IP and Reporter assays were used to confirm the involvement of these genes in transcription of Myristoylated alanine-rich protein kinase C substrate (MARCKS). The sdy mutant mice with a deletion in Dysbindin, which exhibit behavioral abnormalities, and wild-type DBA2J mice were used to investigate MARCKS expression. RESULTS: We revealed an interaction between Dysbindin and NF-YB. DNA chips showed that MARCKS expression was increased in both Dysbindin knockdown cells and NF-YB knockdown cells, and Chromatin IP revealed interaction of these proteins at the MARCKS promoter region. Reporter assay results suggested functional involvement of the interaction between Dysbindin and NF-YB in MARCKS transcription levels, via the CCAAT motif which is a NF-YB binding sequence. MARCKS expression was increased in sdy mutant mice when compared to wild-type mice. CONCLUSIONS: These findings suggest that abnormal expression of MARCKS via dysfunction of Dysbindin might cause impairment of neural transmission and abnormal synaptogenesis. Our results should provide new insights into the mechanisms of neuronal development and the pathogenesis of schizophrenia