Volume 3 Issue 1

Authors: Noubeil Guermat; Azzedine Bellel; Salah Sahli; Patrice Raynaud

Abstract: This paper reports the study of humidity-sensitive and electrical properties plasma polymerization of hexamethyldisiloxane (pp-HMDSO) thin film based sensors. The humidity sensitive film was deposited by glow discharge at low frequency power (19 kHz) in a capacitively coupled parallel plate plasma reactor. The sensor design comprises the interdigitated electrodes and the absorbing layer. The sensor was calibrated in terms of impedance as a function of relative humidity (10% to 95%), using a Frequency Response Analyzer. The signal frequency range was between 102 to 107 Hz with amplitude of 3 V. Hexamethyldisiloxane thin film is investigated as humidity sensor. The deposited film sensor exhibited a small hysteresis (2% RH) and fast response (8 and 34 s for adsorption and desorption between 35% RH and 95% RH, respectively). The results of an electrochemical impedance spectroscopy (EIS) study performed by measuring the sensor's complex impedance, were analyzed and employed to extract equivalent circuit models. Such models have humidity-dependent element values and their structure has a direct relationship with the sensor physics. The performance of the films and the results of the model simulations are herewith presented and discussed. The HMDSO film showed promising characteristics for humidity sensor development.

Keywords: HMDSO; Humidity Sensors; Thin Film; Electrical Characterization; Modeling

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Authors: Haihui Chen; Yingying Zeng

Abstract: This document gives formatting instructions for authors preparing papers for publication in the journal. The authors must follow the instructions given in the document for the papers to be published. You can use this document as both an instruction set and as a template into which you can type your own text. The process of Sulfuric acid heap leaching for uranium mine is widely used in uranium mining and metallurgical industry in China, which includes chemical reactions, liquid membrane diffusion, solid membrane diffusion, etc. Deducing kinetics model and dynamics data will help to guide the work of uranium mine heap leaching. The process style and chemical reaction constants of sulfuric acid leaching for uranium mine are deduced by the curve relationship between the leaching rate and leaching time. Experimental results show that the leaching rate is linear with the leaching time when it is less than 60% and the leaching process is controlled by chemical reaction process. The chemical reaction leaching rate constant is and the liquid-solid phase chemical reaction coefficient is in this experimental data. The experimental results also show that if oxidants were not added into the heap-leaching uranium ore, only 40% of the quadrivalent uranium could be oxidized into hexavalent uranium, so the oxidants must be added to improve the oxidizing ability for greater leaching rate of uranium.

Keywords: Heap Leaching; Uranium; Leaching Rate Constant; Dynamical Model

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Authors: Shigeki Hirasawa; Tomoji Watanabe

Abstract: We studied a simple reaction analysis technique using a network model (NM) to calculate the concentration distribution and deposition rate in a vertical hot-wall-type low-pressure chemical vapor deposition (LPCVD) reactor. We analyzed the deposition rates of poly-silicon film. The calculation results of the deposition rate using the NM analysis agreed with those of the FEM analysis within the difference of 10%. The computation of the NM analysis was 1000 times faster than that of the FEM analysis, indicating that the NM analysis model is effective for shortening computation time without increasing computation error.

Keywords: Chemical Vapor Deposition; Thin Film; Numerical Simulation; Network Model

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Authors: Sascha Bott; Boris Boris Vasilev; Roland Rzehak; Johann W. Bartha

Abstract: In chemical-mechanical planarization (CMP) chip-scale modeling is used to predict the structure height evolutions for a chip layout in combination with a certain process. Usually a test-chip is used for model calibration. The model can then be used for process optimization and control, as well as chip design support. Motivated by a demand for higher accuracy an advanced model for the simulation of the planarization behavior is proposed. It focuses on the mechanical part of CMP. Thus, roughness effects for a more accurate description of pad-wafer-contact on a short scale, which leads to an improved description of local step removal, is included. Furthermore the long scale planarization behavior depending on pattern differences in a chip and the polishing pad used, which leads to a better global step prediction, is considered. The model can be used as a foundation for future investigations on hemical influences.

Keywords: CMP; Chip-scale Modeling; Simulation; Interaction; Pad Roughness; Pattern Influence

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