• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.134.1-134
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• 1998

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.29-32
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• 2000

Cerium oxide thin film has been proposed as a buffer layer between the ferroelectric film and the Si substrate in Metal-Ferroelectric-Insulator-Silicon (MFIS ) structures for ferroelectric random access memory (FRAM) applications. In this study, CeO$_2$thin films were etched with Cl$_2$/Ar gas combination in an inductively coupled plasma (ICP). The highest etch rate of CeO$_2$film is 230 $\AA$/min at Cl$_2$/(Cl$_2$+Ar) gas mixing ratio of 0.2. This result confirms that CeO$_2$thin film is dominantly etched by Ar ions bombardment and is assisted by chemical reaction of Cl radicals. The selectivity of CeO$_2$to YMnO$_3$was 1.83. As a XPS analysis, the surface of etched CeO$_2$thin films was existed in Ce-Cl bond by chemical reaction between Ce and Cl. The results of XPS analysis were confirmed by SIMS analysis. The existence of Ce-Cl bonding was proven at 176.15 (a.m.u.).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.326-329
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• 2002

In this paper, we investigated a feasibility of cerium oxide(CeO$_2$) films as a buffer layer of MFIS(metal ferroelectric insulator semiconductor) type capacitor. CeO$_2$ layer were Prepared by two step process of a low temperature film growth and subsequent RTA (rapid thermal annealing) treatment. By app1ying an ultra thin Ce metal seed layer and N$_2$ Plasma treatment, dielectric and interface properties were improved. It means that unwanted SiO$_2$ layer generation was successfully suppressed at the interface between He buffer layer and Si substrate. The lowest lattice mismatch of CeO$_2$ film was as low as 1.76% and average surface roughness was less than 0.7 m. The Al/CeO$_2$/Si structure shows breakdown electric field of 1.2 MV/cm, dielectric constant of more than 15.1 and interface state densities as low as 1.84${\times}$10$\^$11/ cm$\^$-1/eV$\^$-1/. After N$_2$ plasma treatment, the leakage current was reduced with about 2-order.

• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.3
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• pp.213-225
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• 2002

Metal-Ferroelectric- Insulator- Silicon (MFIS) structured field effect transistor (FET) device was fabricated and characterized. Important issues to realize ferroelectric gate field effect transistor device were summarized in three sections. The choice of interlayer dielectric was made in the consideration of device functionality and chemical reaction between ferroelectric materials and silicon surface during fabrication process. Also, various ferroelectric thin film materials were taken into account to meet desired memory window and process compatibility. Finally, MFIS structured FET device was fabricated and important characteristics were discussed. For feasible integration of current device as random access memory array cell address schemes were also suggested.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.217-220
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• 2001

The possibility of cerium dioxide $(CeO_2)$ thin films as insulators of metal erroelectric insulator semiconductor (MFIS) structures have been studied. The etching $CeO_2$ thin films have been perfonned in an inductively coupled $Cl_{2}/CF_{4}/Ar$ plasma. The high etch rate of the $CeO_2$ thin film was $250\AA /m$ at a 10 % addition of $Cl_2$ into the $Ar(80)/CF_{4}(20)$. The surface reaction of the etched $CeO_2$ thin films was investigated using X-ray photoelectron spectroscopy (XPS) analysis. There are Ce-Cl and Ce-F bonding by chemical reaction between Cl, F and Ce. These products can be removed by the physical bombardment of incident Ar ions.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.675-677
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• 1998

In this paper, we propose the fuzzy inference algorithm with multi-layer structure. MFIS(Multi-layer Fuzzy Inference System) uses PNN(Polynomial Neural networks) structure and the fuzzy inference method. The PNN is the extended structure of the GMDH(Group Method of Data Hendling), and uses several types of polynomials such as linear, quadratic and cubic, as well as the biquadratic polynomial used in the GMDH. In the fuzzy inference method, the simplified and regression polynomial inference methods are used. Here, the regression polynomial inference is based on consequence of fuzzy rules with the polynomial equations such as linear, quadratic and cubic equation. Each node of the MFIS is defined as fuzzy rules and its structure is a kind of neuro-fuzzy structure. We use the training and testing data set to obtain a balance between the approximation and the generalization of process model. Several numerical examples are used to evaluate the performance of the our proposed model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.217-220
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• 2001

The possibility of cerium dioxide (CeO$_{7}$ ) thin films as insulators of metal erroelectric insulator semiconductor (MFIS) structures have been studied. The etching CeO$_2$ thin films have been performed in an inductively coupled C1$_2$/CF$_4$/Ar plasma. The high etch rate of the CeO$_2$ thin film was 250 ${\AA}$/m at a 10% addition of Cl$_2$ into the Ar(80)/CF$_4$(20). The surface reaction of the etched CeO$_2$ thin films was investigated using X-ray photoelectron spectroscopy (XPS) analysis. There are Ce-Cl and Ce-F bonding by chemical reaction between Cl, F and Ce. These products can be removed by the physical bombardment of incident Ar ions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.11a
• /
• pp.29-32
• /
• 2000

Cerium oxide thin film has been proposed as a buffer layer between the ferroelectric film and the Si substrate in Metal-Ferroelectric-Insulator-Silicon (MFIS ) structures for ferroelectric random access memory (FRAM) applications. In this study, CeO$_2$ thin films were etched with Cl$_2$/Ar gas combination in an inductively coupled plasma (ICP). The highest etch rate of CeO$_2$ film is 230 $\AA$/min at Cl$_2$/(Cl$_2$+Ar) gas mixing ratio of 0.2. This result confirms that CeO$_2$ thin film is dominantly etched by Ar ions bombardment and is assisted by chemical reaction of Cl radicals. The selectivity of CeO$_2$ to YMnO$_3$ was 1.83. As a XPS analysis, the surface of etched CeO$_2$ thin films was existed in Ce-Cl bond by chemical reaction between Ce and Cl. The results of XPS analysis were confirmed by SIMS analysis. The existence of Ce-Cl bonding was proven at 176.15 (a.m.u.).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.86-89
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• 2000

The detection technique both the polarization and the mobile charge density at the same time in ferroelectric films on Si using TVS method have been proposed. This method yields a polarizable and an ionic displacement current peaks whose areas are proportional to the total polarization reversal charge and the total moble ionic space charge, respectively. The calculated polarization and the mobile charge density were 0.42 [$\mu$C/$\textrm{cm}^2$] and 5.5$\times$10$^{11}$ (ions/$\textrm{cm}^2$) in the SBT film of MFIS structure measured at 25$0^{\circ}C$, and 1.4 [$\mu$C/$\textrm{cm}^2$] in the LiNbO$_3$ film of MFS structure measured at 30$0^{\circ}C$, respectively.

• Asian Journal of Business Environment
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• v.7 no.2
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• pp.31-38
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• 2017

Purpose - While microfinance institutions(MFIs) from Bangladesh, such as Grameen Bank, received worldwide recognition and the Nobel Peace Prize in 2006, however, there is a paucity of research that provided a comprehensive discussion on the characteristics of the microfinance industry. Hence, the aim of this paper is to discuss some important aspects of the microfinance sector in Bangladesh. Research design, data, and methodology - This study used secondary sources of data, such as annual reports of the Microcredit Regulatory Authority (MRA) and the World Bank database in its descriptive analysis. Results - This study found that Bangladesh has made remarkable progress in her socio-economic and economic development in the last few decades. It is also generally perceived that microfinance has placed significant contribution on such socio-economic development. While microfinance observed unprecedented growth domestically, however, the regulatory framework is still rather weak, and a majority of the MFIs are found to be concentrated in the well-off areas (e.g., Dhaka, Chittagong etc.). Conclusions - The findings are significantly important for the parties who are interested to know the microfinance sector in Bangladesh. To some extent, the findings of this study will provide policy implications that may benefit the industry.