Impact of dopant species on the interfacial trap density and mobility in amorphous In-X-Zn-O solution-processed thin-film transistors

Alloying of In/Zn oxides with various X atoms stabilizes the IXZO structures but generates electron traps in the compounds, degrading the electron mobility. To assess whether the latter is linked to the oxygen affinity or the ionic radius, of the X element, several IXZO samples are synthesized by the sol-gel process, with a large number (14) of X elements. The IXZOs are characterized by XPS, SIMS, DRX, and UV-spectroscopy and used for fabricating thin film transistors. Channel mobility and the interface defect density NST, extracted from the TFT electrical characteristics and low frequency noise, followed an increasing trend and the values of mobility and NST are linked by an exponential relation. The highest mobility (8.5 cm2/Vs) is obtained in In-Ga-Zn-O, and slightly lower value for Sb and Sn-doped IXZOs, with NST is about 2E12 cm2/eV, close to that of the In-Zn-O reference TFT. This is explained by a higher electronegativity of Ga, Sb, and Sn than Zn and In, their ionic radius values being close to that of In and Zn. Consequently, Ga, Sb, and Sn induce weaker perturbations of In-O and Zn-O sequences in the sol-gel process, than the X elements having lower electronegativity and different ionic radius. The TFTs with X = Ca, Al, Ni and Cu exhibited the lowest mobility and NST > 1E13 cm2/eV, most likely because of metallic or oxide clusters formation

Applications and benefits of digital human models to improve the design of workcells in car’s manufacturing plants according to international standards

During last years, the car’s manufacturing process has deeply changed because of several factors affected the automotive global scenario. As a consequence, design methodologies of the plant’s workcells have changed. In particular, ergonomics for manufacturing system has become a key factor to improve product’s quality, safety and work organization. In this paper, the authors show the approach used in Fiat Group Automobiles (FGA) based on simulation tools to analyse ergonomic aspects of work-cells already in design phase. Simulation tools allow a deep postural analysis that is one of the main criticism in the design phase. The principles of Digital Human Modeling have been used to develop an easy internal virtual manikin, the Human Model. The tool, based on ISO standards and on a worldwide anthropometric database, allows designers to simulate the most probable postures engaged by operator during work tasks as well as to validate improvements and corrective actions

ANALYTICAL MODELS AND ELECTRICAL CHARACTERISATION OF ADVANCED MOSFETS IN THE QUASI BALLISTIC REGIME

International audienceThe quasi-ballistic nature of transport in end of the roadmap MOSFETs device is expected to lead to significant on state current enhancement. The current understanding of such mechanism of transport is carefully reviewed in this chapter, underlining the derivation and limits of corresponding analytical models. In a second part, different strategies to compare these models to experiments are discussed, trying to estimate the "degree of ballisticity" achieved in advanced technologies

Non-Arrhenius conduction due to the interface-trap-induced disorder in X-doped amorphous InXZnO thin-film transistors

Thin film transistors, with channels composed of In-X-Zn oxides, IXZO, with X dopants: Ga, Sb, Be, Mg, Ag, Ca, Al, Ni, and Cu, were fabricated and their I-V characteristics were taken at selected temperatures in the 77K<T<300K range. The low field mobility, mu, and the interface defect density, Nst were extracted from the characteristics for each of the studied IXZOs. At higher T the mobility follows the Arrhenius law with an upward distortion, increasing as T was lowered, gradually transforming into the exp [-(T0/T)1/4] variation. We showed that mu(T, Nst) follows mu0exp[-Eaeff(T,Nst)/kT], with T-dependent effective activation energy Eaeff(T, Nst) accounts for the data, revealing a linear correlation between Eaeff and Nst at higher T. Temperature variation of Eaeff(T, Nst) was evaluated using a model assuming a random distribution of conduction mobility edge Ec values in the oxides, stemming from spatial fluctuations induced by disorder in the interface traps distribution. For a Gaussian distribution of Ec, the activation energy Eaeff(T, Nst) varies linearly with 1/T, which accounts satisfactorily for the data obtained on all the studied IXZOs. The model also shows that Eaeff(T, Nst) is a linear function of Nst at a fixed T, which explains the exponential decrease of mu with NST

A New Technique to Extract the Gate Bias Dependent S/D Series Resistance of Sub-100nm MOSFETs

International audienceIn this study, a new technique to extract the S/D series resistance (Rsd) from the total resistance versus transconductance gain plot Rtot(1/beta) is proposed. The technique only requires the measurement of Id(Vgs)|Vgt and beta, allowing fast and statistical analysis in an industrial context. Unlike the usual Rtot(L)-based techniques, it has the advantage of being insensitive to the channel length and mobility variations and finally enables to extract very accurate values for Rsd(Vgs) and the effective mobility reduction factor mueff(Vgt)/mueff(0)

Analysis of effective mobility and hall effect mobility in high-k based In0.75Ga0.25As metal-oxide-semiconductor high-electron-mobility transistors

We report an In0.75Ga0.25As metal-oxide-semiconductor high-electron-mobility transistor with a peak Hall mobility of 8300 cm(2)/Vs at a carrier density of 2 x 10(12) cm(-2). Comparison of split capacitance-voltage (CV) and Hall Effect measurements for the extracted electron mobility have shown that the split-CV can lead to an overestimation of the channel carrier concentration and a corresponding underestimation of electron mobility. An analysis of the electron density dependence versus gate voltage allows quantifying the inaccuracy of the split-CV technique. Finally, the analysis supported by multi-channel conduction simulations indicates presence of carriers spill over into the top InP barrier layer at high gate voltages. (C) 2011 American Institute of Physics. (doi: 10.1063/1.3665033

Heterogeneous integration of KY(WO4)2-on-glass : a bonding study

Rare-earth ion doped potassium yttrium double tungstate, RE: KY(WO4)(2), is a promising candidate for small, power-efficient, on-chip lasers and amplifiers. There are two major bottlenecks that complicate the realization of such devices. Firstly, the anisotropic thermal expansion coefficient of KY(WO4)(2) makes it challenging to integrate the crystal on glass substrates. Secondly, the crystal layer has to be, for example, < 1 mu m to obtain single mode, high refractive index contrast waveguides operating at 1550 nm. In this work, different adhesives and bonding techniques in combination with several types of glass substrates are investigated. An optimal bonding process will enable further processing towards the manufacturing of integrated active optical KY(WO4)(2) devices. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

Physics of the frequency response of rectifying organic Schottky diodes

International audienceThe frequency response of unipolar organic Schottky diodes used in a rectifying circuit, such as an RFID tag, has been investigated in detail. The time dependent response of rectifying circuits has been simulated solving both the Drift Diffusion and Poisson equations to model the hole transport within the diode, coupled with time dependent circuit equations. Several approximations have also been discussed. It turns out that the cut off frequency of the rectifying circuit is indeed limited by the carrier time-of-flight and not by the diode equivalent capacitance. Simulations have also been confirmed by comparison with experiments, involving diodes with different mobilities and thicknesses. This work confirms that the 13.56MHz frequency can be reached using polymer semiconductors, as already experimentally demonstrated in the literature, by an adequate control of the active layer thicknes

Low-frequency noise in junctionless multigate transistors

Low-frequency noise in n-type junctionless multigate transistors was investigated. It can be well understood with the carrier number fluctuations whereas the conduction is mainly limited by the bulk expecting Hooge mobility fluctuations. The trapping/release of charge carriers is related not only to the oxide-semiconductor interface but also to the depleted channel. The volume trap density is in the range of 6-30 x 10(16) cm(-3) eV(-1), which is similar to Si-SiO2 bulk transistors and remarkably lower than in high-k transistors. These results show that the noise in nanowire devices might be affected by additional trapping centers. (C) 2011 American Institute of Physics. (doi:10.1063/1.3569724

Commande « sans modèle » pour l'asservissement numérique d'un banc de caractérisation magnétique

International audience Dans cet article, nous présentons une stratégie innovante d'asservissement numérique destinée à piloter un banc de caractérisation de matériaux magnétiques doux de type cadre Epstein. L'objectif est d'imposer la forme de l'induction magnétique quelle que soit l'excitation et le matériau. Compte- tenu du caractère non-linéaire des courbes d'aimantation des matériaux magnétiques, une commande originale de type « sans modèle » est considérée. Les propriétés dynamiques en boucle fermée permettent d'assurer une certaine robustesse vis-à-vis des modifications du point de fonctionnement associées essentiellement à la forme de l'hystérésis magnétique. Le fonctionnement et les performances de l'asservissement sont illustrés à la fois par des simulations basées sur le modèle d'hystérésis magnétique de Jiles-Atherton et expérimentalement.  </div