• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.2
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• pp.111-124
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• 2002

The ferroelectric RAM (FeRAM) has a great advantage for a system on a chip (SOC) and mobile product memory, since FeRAM not only supports non-volatility but also delivers a fast memory access similar to that of DRAM and SRAM. This work develops at three levels: 1) low voltage operation with boost voltage control of bitline and plateline, 2) reducing bitline capacitance with multiple divided sub cell array, and 3) increasing chip performance with write operation sharing both active and precharge time period. The key techniques are implemented on the proposed hierarchy bitline scheme with proposed hybrid-bitline and high voltage boost control. The test chip and simulation results show the performance of sub-1.5 voltage operation with single step pumping voltage and self-boost control in a cell array block of 1024 ($64{\;}{\times}{\;}16$) rows and 64 columns.

• Journal of the Korean Electrochemical Society
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• v.2 no.3
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• pp.130-133
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• 1999

In this work, a capacitance-type alcohol gas sensor using porous silicon layer is developed to apply for breath alcohol measurement and its characteristics are estimated at room temperature. Current alcohol sensors using metal oxides such as tin-oxide are not only difficult to measure low alcohol concentration, but also should heat at $200\;to\;400^{\circ}C$ to improve the sensitivity. But the sensor using porous silicon layer has good sensitivity even at room temperature by very large effective surface area and suitable structure to fabricate integrated micro sensors. In the experiment, the capacitance was measured for the range of 0 to $0.5\%$ alcohol concentration with the interval of $0.05\%$, in which alcohol solution was kept at 25, 36, and $45^{\circ}C$ by a heater. As the result, good linearity was observed and the capacitance increased about 1.1, 2.6 and $4.6\%$ per the increment of $0.1\%$ alcohol concentration each temperature, respectively, at the frequency of 120 Hz.

• Journal of IKEEE
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• v.6 no.1 s.10
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• pp.47-53
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• 2002

This paper manufacturing one system and use this separatively, plan, and embody system that apply integration design method in research about characteristic of internal core of 8051 micro-processors and system reusability so that can use as module of other system. The proposed system itself by object style so that reusability may be possible in proposed method and object style for connection between this systems is required. Set on these request and when systems have own information and were linked with other systems, by supplying own information automatic movement itself is realized and system itself embodies ashes so that can be applied to other system. The proposed method in this paper analyzes and compares with existent Z-80 education board, as well as system that propose offers extensibility, it handles most function to software and development period, expense and baud dimension confirmed advantage of and so on that reduce. Also, design for object style system architecture and showed feature that extensibility and portability are augmented.

• Journal of IKEEE
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• v.11 no.4
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• pp.205-212
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• 2007

The ubiquitous sensor network consists of micro sensors with wireless communication capabilities. Compared to wired communication, wireless communication is more subject to eavesdropping as well as data variation and manipulation. Accordingly, there must be efforts to secure the information delivered over the sensor network. Providing security to the sensor network, however, requires additional energy consumption, which is an important issue since energy transformation is difficult to implement in a sensor network. This paper proposes a routing mechanism based on the energy-efficient cluster that features security functions capable of safely processing the data acquired from the sensor network. The proposed algorithm reduces energy consumption by fixing the clusters formed at the initial stage and using the pre-distribution scheme so that the cluster and node keys generated and exchanged at the initial stage are not re-generated or re-exchanged. Simulation experiments confirmed that the proposed approach reduces energy consumption compared to implementing security measures to the conventional cluster-based routing mechanism.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.389.2-389.2
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• 2014

Polydimethylsiloxane (PDMS) based electronic devices are widely used for various applications in large area electronics, biomedical wearable interfaces and implantable circuitry where flexibility and/or stretchability are required. A few fabrication methods of electronic devices directly on PDMS substrate have been reported. However, it is well known that micro-cracks appear in the metal layer and in the lithography pattern on a PDMS substrate. To solve the above problems, a few studies for fabrication of stiff platform on PDMS substrate have been reported. Thin-film islands of a stiff region are fabricated on an elastomeric substrate, and electronic devices are fabricated on these stiff islands. When the substrate is stretched, the deformation is mainly accommodated by the substrate, and the stiff islands and electronic devices experience relatively small strains. Here, we report a new method to achieve stiff islands structures on an elastomeric substrate at a various thickness, as the platform for stretchable electronic devices. The stiff islands were defined by conventional photolithography on a stress-free elastomeric substrate. This technique can provide a practical strategy for realizing large-area stretchable electronic circuits, for various applications such as stretchable display or wearable electronic systems.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.432-434
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• 2006

The additional matters appear to be considered in several aspects for building up power-quality measuring system of transmission system(high voltage system) compared to distribution system(middle or low voltage system). Like in distribution system, input signals are also received from PT and CT source of voltage and current respectively in transmission system and applied in accordance with a certain rate. In this case, very big error rate can be occurred according to the specification of the measuring system as the applying rate is bigger than in distribution system beyond comparison. In addition, when the abnormal signal occurred such as sag/swell, interruption, transient etc., power quality of other sires linked to the system also should be checked to find the accurate cause of the abnormal power-quality signals from the corresponding. site. Accordingly, the accurate diagnosis on the condition of power quality for the system depends on the way how the synchronization system is brought along for each site. This paper will suggest the solution for the most effective system building focused on how to solve the problem of the error rate and synchronization described in the above when building up the measuring system of power quality for transmission system.

• 전자공학회논문지 IE
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• v.48 no.2
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• pp.6-11
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• 2011

This paper describes the design of new method of propagation delay measurement in micro and nanostructures during characterization of ASIC standard library cell. Providing more accuracy timing information about library cell (NOR, AND, XOR, etc.) to the design team we can improve a quality of timing analysis inside of ASIC design flow process. Also, this information could be very useful for semiconductor foundry team to make correction in technology process. By comparison of the propagation delay in the CMOS element and result of analog SPICE simulation, we can make assumptions about accuracy and quality of the transistor's parameters. Physical implementation of phase error accumulation method(PHEAM) can be easy integrated at the same chip as close as possible to the device under test(DUT). It was implemented as digital IP core for semiconductor manufacturing process($0.11{\mu}m$, GL130SB). Specialized method helps to observe the propagation time delay in one element of the standard-cell library with up-to picoseconds accuracy and less. Thus, the special useful solutions for VLSI schematic-to-parameters extraction (STPE), basic cell layout verification, design simulation and verification are announced.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1828-1835
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• 2012

In this paper, a conceptual design and a detailed design of novel cylindrical magnetic levitation stage is introduced. This is came from planar-typed magnetic levitation stage. The proposed stage is composed of cylinder-typed permanent magnet array and semi-cylinder-typed 3 phase winding module. When a proper current is induced at winding module, a magnetic levitation force between the permanent magnet array and winding module is generated. The proposed stage can precisely move the cylinder to rotations and translations as well as levitations with the magnetic levitation force. This advantage is useful to make a nano patterning on the surface of cylindrical specimen by using electron beam lithography under vacuum. Two methods are used to calculate required magnetic levitation forces. The one is 2D FEM analysis, the other is mathematical modeling. This paper shown that results of two methods are similar. An assistant plate is introduced to reduce required currents of winding module for levitations in vacuum. The mathematical model of cylindrical magnetic levitation stage is used for dynamic simulation of magnetic levitations. A lead-lag compensator is used for control of the model. Simulation results shown that the detail designed model of the cylindrical magnetic levitation stage with the assistant plate can be controlled very well.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2251-2253
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• 2000

MEMS기술을 이용하여 단층 실리콘 나이트라이드($Si_{3}N_4$) 다이아프램을 제조하고, 이 다이아프램상에 저항성 가열 진공증착법과 고주파 마그네트론 스퍼터링법을 이용하여 차례로 In막과 ZnO막을 증착하고, In의 도핑을 위해 열처리하여 $NH_3$ 가스 감지용 마이크로센서를 제작하였다. 감지막의 열처리온도에 따른 구조적 및 전기적 특성은 XRD, SEM, AFM, 4-point probe 및 Electrometer를 통하여 각각 조사하였다. 제작된 센서의 열처리온도와 인가전력에 따라 $NH_3$ 가스에 대한 감도, 선택성 및 시간응답 특성을 조사하였다. 감지막 두께 3000 ${\AA}$, 열처리온도 400$^{\circ}C$로 제조된 마이크로 센서가 히터 인가전력 366 mW에서 100 ppm의 $NH_3$ 가스농도에서 대하여 16 %, 350 ppm의 가스농도에서 대하여 23 %의 가장 우수한 감도를 나타내었다. 그러나 CO 가스 및 $NO_x$ 가스에 대한 감지특성은 관찰되지 않았다.

• Korean Journal of Optics and Photonics
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• v.20 no.6
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• pp.334-338
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• 2009

Recently, with increasing demand for flat-panel display product, methods for large area patterning are required. TIR (total internal reflection) holographic photo-lithography isstudied as one of the methods of large area lithography. In conventional TIR holography, light sources for hologram recording and image reconstruction are coherent beams such as laser beams. If the image is reconstructed with an incoherent light source such a UV lamp, the image noise from the coherence of light will be reduced and the UV lamp will be a better light source for large area exposure. We analyzed the effect of spectral bandwidth and angular bandwidth of the light source in image reconstruction and verified image blurring with experiments. For large area patterning which has micro-scale line width, it is expected that TIR holographic photo lithography by UV lamp will become a low-noise and low-priced technique.