• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.54-62
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• 2001

This paper describes a new method for measuring the changes in specific surface asperities arising from processes such as finishing, coating, wear and corrosion. In repetitive measurements, relocation device gives the same position and orientation so that specific profile can be obtained. A low-cost relocation device is designed and its performance is assessed. The error in relocation process is compensated by statistic compensation algorithm. And, a removing process of cusp by grinding is observed by the proposed method.

• Journal of Electrical Engineering and information Science
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• v.2 no.4
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• pp.106-110
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• 1997

A new SOI NMOSFET with a 'LOCOS-like' shape self-aligned polysilicon gate formed on the recessed channel region has been fabricated by a mix-and-match technology. For the first time, a new scheme for implementing self-alignment in both source/drain and gate structure in recessed channel device fabrication was tried. Symmetric source/drain doping profile was obtained and highly symmetric electrical characteristics were observed. Drain current measured from 0.3${\mu}{\textrm}{m}$ SOI devices with V\ulcorner of 0.77V and Tox=7.6nm is 360$mutextrm{A}$/${\mu}{\textrm}{m}$ at V\ulcorner\ulcorner=3.5V and V\ulcorner=2.5V. Improved breakdown characteristics were obtained and the BV\ulcorner\ulcorner\ulcorner(the drain voltage for 1 nA/${\mu}{\textrm}{m}$ of I\ulcorner at V=\ulcorner\ulcorner=0V) of the device with L\ulcorner\ulcorner=0.3${\mu}{\textrm}{m}$ under the floating body condition was as high as 3.7 V. Problems for the new scheme are also addressed and more advanced device structure based on the proposed scheme is proposed to solve the problems.

• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.127-132
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• 2012

This study discusses photoresist forming using a composite grayscale to fabricate a Fresnel lens. Grayscale lithography is a common production method used to facilitate the forming of lenses with different curvatures and depths. However, this approach is time consuming and expensive. This study proposes a method for overcoming these obstacles by integrating a digital micromirror device and microscope to supplant the traditional physical grayscale mask. This approach provides a simple and practical maskless optical lithography system. According to the results, the two adjacent grayscales displayed substantial differences between the high grayscale and influence the low grayscale that ultimately affected photoresist formation. Furthermore, we show that change of up to 150% in the slope can be achieved by changing the grayscale gradient in the central zone and the ring profile. The results of the optical experiment show a focus change with different gray gradients.

• 연구논문집
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• s.28
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• pp.89-100
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• 1998

This paper deals with the design and analysis of a beating cam. The beating device of a high speed rapier loom, weaving fabric by completion of warp-weft patterns, is driven by double cam type on the same axis. As the double cam, coupled with two cams, performs the mutual conjugate motion, the double cam must be very preciously designed for smooth. For the shape design of a double cam, an instant velocity center method is proposed. This method can determine the cam profile from the contact conditions of the cam and roller follower and the velocity relationships at the instant velocity center. And the practical applicability was verified by developing “DISKCAM of a CAD program. As the results in this paper, the shapes of two cams, which are in the conjugate motion, are designed by instant velocity center method. We applied 8-order polynominals for the beating as displace¬ment curves for shape determination of double cams. The data of displacement, velocity, and acceleration of beating cam can be used adjust in accurate operation and to develope an advanced beating device.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.2
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• pp.107-117
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• 2010

An analytical subthreshold swing model is presented for symmetric double-gate (DG) MOSFETs with Gaussian doping profile in vertical direction. The model is based on the effective conduction path effect (ECPE) concept of uniformly doped symmetric DG MOSFETs. The effect of channel doping on the subthreshold swing characteristics for non-uniformly doped device has been investigated. The model also includes the effect of various device parameters on the subthreshold swing characteristics of DG MOSFETs. The proposed model has been validated by comparing the analytical results with numerical simulation data obtained by using the commercially available $ATLAS^{TM}$ device simulator. The model is believed to provide a better physical insight and understanding of DG MOSFET devices operating in the subthreshold regime.

• Journal of the Optical Society of Korea
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• v.16 no.3
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• pp.221-227
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• 2012

We propose optical proximity corrections (OPCs) for digital micromirror device (DMD)-based maskless lithography. A pattern writing scheme is analyzed and a theoretical model for obtaining the dose distribution profile and resulting structure is derived. By using simulation based on this model we were able to reduce the edge placement error (EPE) between the design width and the critical dimension (CD) of a fabricated photoresist, which enables improvement of the CD. Moreover, by experiments carried out with the parameter derived from the writing scheme, we minimized the corner-rounding effect by controlling light transmission to the corners of a feature by modulating a DMD.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.253-255
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• 2003

Electricity is the prime commodity in mobile device, e.g. smart phone, PDA, MP3 player and etc. This strict restriction on power consumption requirement of the mobile device puts unique demand in designing hardware and software components of the device. In this paper, we address the issue of minimizing the power consumption in retrieving the continuous media data from the disk drive for real-time playback purpose. Different from the legacy text based data, real-time multimedia playback requires that the storage supplies the data block continuous fashion. This may put immense burden on the power scarce environment since the disk Is required to be active for the entire playback duration. We develop elaborate algorithm which carefully analyzes the power consumption profile of the disk drive and which establishes the data retrieval schedule for the given playback. It computes the amount of data blocks to read, the length of active and standby period. According to our simulation result, the ARM algorithm exhibits superior performance in continuous media retrieval from the aspect of power consumption to legacy playback scheme.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.2
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• pp.23-27
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• 1976

$Si{\cdot}SnO_{2}$ heterojunction was prepared by oxidzing at oxygen atmosphere $SnO_{2-X}$ Which made by Flith evaporation of $SnO_{2}$ powder on III surface of p and n type Si single crystals. The energy band Profile of $Si{\cdot}SnO_{2}$ heterojunction was depicted from its physical properties. This heterojunction was very good rectifying junction, very sensitive in spectral response of Photovoltage at from 400nm to 1200nm, and -10$^{18}$sec of time contant. From above properties, this heterojunction was found ps good high speed photovoltaic device and solar cell.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.903-908
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• 2015

This paper has analyzed threshold voltage shift for doping profile of asymmetric double gate(DG) MOSFET. Ion implantation is usually used in process of doping for semiconductor device and doping profile becomes Gaussian distribution. Gaussian distribution function is changed for projected range and standard projected deviation, and influenced on transport characteristics. Therefore, doping profile in channel of asymmetric DGMOSFET is affected in threshold voltage. Threshold voltage is minimum gate voltage to operate transistor, and defined as top gate voltage when drain current is $0.1{\mu}A$ per unit width. The analytical potential distribution of series form is derived from Poisson's equation to obtain threshold voltage. As a result, threshold voltage is greatly changed by doping profile in high doping range, and the shift of threshold voltage due to projected range and standard projected deviation significantly appears for bottom gate voltage in the region of high doping concentration.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1287-1295
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• 2015

Recently, fieldbus communication technologies have been widely deployed for industrial automation because they are profitable in providing easy system integration and management for multiple devices, as well as high-speed communication. It is essential for smart encoders to support fieldbus connectivity, where the device configuration and various types of information related to position are exchanged between an external controller and multiple encoders over the communication link. In this study, we implemented the CiA 406 device profile for smart encoders from the CANopen standards by extending an open-source CANopen standard-compliant framework, called CanFestival. The CiA 406 functionalities implemented in this study were validated on a test-bed consisting of a CANopen master and virtual CANopen encoders with our CiA 406 extension module.