• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
• /
• pp.7-11
• /
• 2002

In this study, Au thin films were etched with a $Cl_2/Ar$ gas combination in an in an inductively coupled plasma. The etch properties were measured for different gas mixing ratios of $Cl_2/(Cl_2+Ar)$ while the other process conditions were fixed at rf power (700 W), dc bias voltage (150 V), and chamber pressure (15 mTorr). The highest etch rate of the Au thin film was 3500 $\AA/min$ and the selectivity of Au to $SiO_2$ was 4.38 at a $Cl_2/(Cl_2+Ar)$ gas mixing ratio of 0.2. The surface reaction of the etched Au thin films was investigated using x-ray photoelectron spectroscopy (XPS) analysis. There is Au-Cl bonding by chemical reaction between Cl and Au. During the etching of Au thin films in $Cl_2/Ar$ plasma, Au-Cl bond is formed, and these products can be removed by the physical bombardment of Ar ions. In addition, Optical emission spectroscopy (OES) were investigated to analyze radical density of Cl and Ar in plasma. The profile of etched Au investigated with scanning electron microscopy (SEM).

• Transactions on Electrical and Electronic Materials
• /
• 제14권1호
• /
• pp.12-15
• /
• 2013

In this study, we carried out an investigation of the etching characteristics (etch rate, and selectivity to $SiO_2$) of $ZrO_2$ thin films in a $CF_4$/Ar inductively coupled plasma (ICP) system. The maximum etch rate of 60.8 nm/min for $ZrO_2$ thin films was obtained at a 20 % $CF_4/(CF_4+Ar)$ gas mixing ratio. At the same time, the etch rate was measured as a function of the etching parameter, namely ICP chamber pressure. X-ray photoelectron spectroscopy (XPS) analysis showed efficient destruction of the oxide bonds by the ion bombardment, as well as an accumulation of low volatile reaction products on the etched surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch characteristics for the $CF_4$-containing plasmas.

• 한국전기전자재료학회논문지
• /
• 제11권6호
• /
• pp.472-476
• /
• 1998

The surface reactions of silica film($SiO_2-P_2O_5-B_2O_3-GeO_2$) with fluorocarbon plasma has been studied by using angle -resolved x-ray photoelectron spectroscopy(XPS). It has been confirmed that residual carbon consists of C-C and C-CFx bonds and fluorine mainly binds silicon in the case of etched silica by using $CF_4$ gas plasma. The surface reaction of silica with various fluorocarbon gases, such as $CF_4,C_2F_6 and CHF_3$ were investigated. XPS results showed that though the etching gases were changed, the elements and binding states of the residual layers on the etched silica by using various fluorocarbon gas plasma were nearly the same . This seems to be due to the high volatility of byproducts, that is, $SiF_4 and CO_2$ etc..

• Transactions on Electrical and Electronic Materials
• /
• 제4권3호
• /
• pp.1-4
• /
• 2003

The etching of Au thin films has been performed in an inductively coupled $CF_4 / Cl_2 / Ar$ plasma. The etch properties including etch rate and selectivity were examined as $CF_4$ content adds from o to $30\%$ to $Cl_2/Ar$ plasma. The $Cl_2/(Cl_2 + Ar)$ gas mixing ratio was fixed at $20\%$. Other parameters were fixed at an rf power of 700 W, a dc bias voltage of -150 V, a chamber pressure of 15 mTorr, and a substrate temperature of $30^{\circ}C$. The highest etch rate of the Au thin film was 370 nm/min at a $10\%$ additive $CF_4$ into $Cl_2/Ar$ gas mixture. The surface reaction of the etched Au thin films was investigated using x-ray photoelectron spectroscopy (XPS) analysis. The XPS analysis shows that the intensities of Ail peaks are changed, indicating that there is a chemical reaction between Cl and Au. Au-Cl is hard to remove on the surface because of its high melting point. However, etching products can be sputtered by Ar ion bombardment.

• 한국전기전자재료학회논문지
• /
• 제25권9호
• /
• pp.681-685
• /
• 2012

We investigated the dry etching characteristics of TiN in $TiN/Al_2O_3$ gate stack using a inductively coupled plasma system. TiN thin film is etched by BCl3/He plasma. The etching parameters are the gas mixing ratio, the RF power, the DC-bias voltages and process pressures. The highest etch rate is in $BCl_3/He$ (25%:75%) plasma. The selectivity of TiN thin film to $Al_2O_3$ is pretty similar with $BCl_3/He$ plasma. The chemical reactions of the etched TiN thin films are investigated by X-ray photoelectron spectroscopy. The intensities of the Ti 2p and the N 1s peaks are modified by $BCl_3$ plasma. Intensity and binding energy of Ti and N could be changed due to a chemical reaction on the surface of TiN thin films. Also we investigated that the non-volatile byproducts such as $TiCl_x$ formed by chemical reaction with Cl radicals on the surface of TiN thin films.

• 전기화학회지
• /
• 제11권4호
• /
• pp.227-241
• /
• 2008

This article involves a unified treatment of equilibrium thermodynamics of the chemical reaction coupled with other interfacial (phase boundary) reactions. The modified (restrictive) chemical potential ${\mu}_k^+$, such as electrochemical potential, hydrostatic-chemical (mechanochemical) potential (exceptionally in the presence of the pressure difference) and surface-chemical potential, was first introduced under the isothermal and isobaric conditions. This article then enlightened the equilibrium conditions in case where the release of chemical energy is counterbalanced by the supply of electrical energy, by the supply of hydrostatic work (exceptionally in the presence of ${\Delta}p$), and finally by the release of surface energy, respectively, at constant temperature T and pressure p in terms of the modified chemical potential ${\mu}_k^+$. Finally, this paper focussed on the difference between chemical and electrochemical equilibria based upon the fundamentals of the isothermal and isobaric equilibrium conditions described above.

• Computers and Concrete
• /
• 제19권3호
• /
• pp.315-323
• /
• 2017

Within the context of continuum mechanics, inelastic behaviours of constitutive responses are usually modelled by using phenomenological approaches. Elasto-plastic damage modelling is extensively used for concrete material in the case of progressive strength and stiffness deterioration. In this paper, a review of the main features of elasto-plastic damage modelling is presented for uniaxial stress-strain relationship. It has been reported in literature that the influence of Alkali-Silica Reaction (ASR) can lead to severe degradations in the modulus of elasticity and compression strength of the concrete material. In order to incorporate the effects of ASR related degradation, in this paper the constitutive model of concrete is based on the coupled damage-plasticity approach where degradation in concrete properties can be captured by adjusting the yield and damage criteria as well as the hardening moduli related parameters within the model. These parameters are adjusted according to results of concrete behaviour from the literature. The effect of ASR on the dynamic behaviour of a beam and a column are illustrated under moving load and cyclic load cases.

• Journal of applied mathematics & informatics
• /
• 제35권3_4호
• /
• pp.277-302
• /
• 2017

In this paper, we have proposed a numerical method for Singularly Perturbed Boundary Value Problems (SPBVPs) of reaction-diffusion type of third order Ordinary Differential Equations (ODEs). The SPBVP is reduced into a weakly coupled system of one first order and one second order ODEs, one without the parameter and the other with the parameter ${\varepsilon}$ multiplying the highest derivative subject to suitable initial and boundary conditions, respectively. The numerical method combines boundary value technique, asymptotic expansion approximation, shooting method and finite difference scheme. The weakly coupled system is decoupled by replacing one of the unknowns by its zero-order asymptotic expansion. Finally the present numerical method is applied to the decoupled system. In order to get a numerical solution for the derivative of the solution, the domain is divided into three regions namely two inner regions and one outer region. The Shooting method is applied to two inner regions whereas for the outer region, standard finite difference (FD) scheme is applied. Necessary error estimates are derived for the method. Computational efficiency and accuracy are verified through numerical examples. The method is easy to implement and suitable for parallel computing. The main advantage of this method is that due to decoupling the system, the computation time is very much reduced.

• Bulletin of the Korean Chemical Society
• /
• 제24권12호
• /
• pp.1751-1756
• /
• 2003

An electrochemical study related to the electroreduction of 4-amino-6-methyl-3-thio-1,2,4-triazin-5-one(I), 6-methyl-3-thio-1,2,4-triazin-5-one(II), and 2,4-dimetoxy-6-methyl-1,3,5-triazine(III) in dimethylformamide at glassy carbon electrode has been performed. A variety of electrochemical techniques, such as differential pulse voltammetry (DPV), cyclic voltammetry (CV), chronoamperometry, and coulometry were employed to clarify the mechanism of the electrode process. The compounds I and II with thiol group exhibited similar redox behavior. Both displayed two cathodic peaks, whereas the third compound, III, without thiol group showed only one cathodic peak in the same potential range of the second peak of I and II. The results of this study suggest that in the first step the one electron reduction of thiol produced a disulfide derivative and in the second reduction step the azomethane in the triazine ring was reduced in two electron processes. A reduction mechanism for all three compounds is proposed on this basis. In addition, some numerical constants, such as diffusion constant, transfer coefficient, and rate constant of coupled chemical reaction in the first reduction peak were also reported.

• 한국전기전자재료학회논문지
• /
• 제26권1호
• /
• pp.1-5
• /
• 2013

In this paper, we investigated the etching characteristics of the TaN thin films and the surface reaction of TaN thin films after etching process. The etching characteristics of the TaN thin films were carried out using inductively coupled plasma (ICP). The etch rate and the selectivity of TaN to $SiO_2$ and TaN to PR were measured by varying the gas mixing ratio, RF power, DC-bias voltage, and process pressure in CF-based plasma. The surface reaction of TaN thin films were determined by x-ray photoelectron spectroscopy (XPS).