• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.801-806
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• 1986

The effect of SiH2Cl2 -HCl gas on the growth rate of epitaxial layer is studied. The temperature, pressure and gas mixing ratio of SiH2Cl2 and HCl are varied to study the growth rate dependence and selective Si epitaxy. The P-n junction diode is fabricated on the epitaxial layer and electrical characteristics are examined. Also, using selective Si epitaxy, a possibility of thin dielectric isolation process, that gives an independent isolation width on the mask dimension, is examined.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.77-77
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• 2009

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1458-1470
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• 2018

In this letter, a new dual-port Multiple-Input Multiple-Output (MIMO) antenna is introduced which has two independent signal feeding ports in a single antenna element to achieve smaller antenna volumes for the 5G mobile applications. The dual-port structure is implemented by adding a cross coupled semi-loop (CCSL) antenna as the secondary radiator to the ground short of inverted-F antenna (IFA). It is found that the port to port isolation is not deteriorated when an IFA and CCSL is combined to form a dual-port structure. The isolation property of the proposed antenna is compared with a polarization diversity based dual-port antenna proposed in the literature [9]. The operating frequency range is 3.3-4.0 GHz which is suitable for places where $4{\times}4$ MIMO systems are supposed to be deployed such as in China, EU, Korea and Japan at the band ${\times}$ (3.3 - 3.8GHz. The measured 6-dB impedance bandwidths of the proposed antennas are larger than 700 MHz with isolation between the feeding ports higher than 18 dB [1-2]. The simulation and measurement results show that the proposed antenna concept is a very promising alternative for 5G mobile applications.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.402-409
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• 2013

An innovative application of voltage-contrast (VC) inspection allowed inline detection of NMOS leakage in dense SRAM cells is presented. Cell sizes of SRAM are continual to do the shrinkage with bit density promotion as semiconductor technology advanced, but the resulting challenges include not only development of smaller-scale devices, but also intra-devices isolation. The NMOS leakage caused by the underneath n+/P-well shorted to the adjacent PMOS/N-well was inspected by the proposed electron-beam (e-beam) scan in which VC images were compared during the in-line process step of post contact tungsten (W) CMP (Chemical Mechanical Planarization) instead of end-of-line electrical test, which has a long response time. A series of experiments based on the mechanism for improving the intra-well isolation was performed and verified by the inline VC inspection. An optimal process-integration condition involved to the tradeoff between the implant dosage and photo CD was carried out.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.922-923
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• 2008

This paper is proposed to a novel DC-DC buck-boost converter added electric isolation by using a soft switching method. To be achieved of high efficiency system, the proposed converter is constructed by using a partial resonant circuit. The control switches using in the converter are operated with soft switching for a partial resonant method. The controlling switches are operated without increasing their voltage and current stresses by the soft switching technology. The result is that the switching loss is very low and the converter efficiency is high. And the proposed converter is added in a electric isolation. When the power conversion system is required to electric isolation, the proposed converter is adopted with system development of high efficiency. The soft switching operation and the system efficiency of the proposed converter is verified by digital simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.142-144
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• 2008

This paper is studied on the characteristic analyses of a high performance buck-boost converter added electric isolation by using a soft switching method. To be achieved of a high performance system, the proposed buck-boost converter is constructed by using a partial resonant circuit. The control switches using in the converter are operated with soft switching for a Partial resonant method. The controlling switches are operated without increasing their voltage and current stresses by the soft switching technology. The result is that the switching loss is very low and the converter efficiency is high. And the proposed converter is added in a electric isolation. When the power conversion system is required to electric isolation, the proposed converter is adopted with the system development of high efficiency. The soft switching operation and system efficiency of the proposed converter is verified by digital simulation and experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.13-20
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• 2010

Due to the recent quantum leaps forward in bio-, nano-, and information-technologies, the precisionization and miniaturization of mechanical and electrical components are in high demand. The allowable margin for vibration limits for such equipments is becoming stricter. In order to meet this demand, understandings on the characteristics of vibration isolation systems are highly required. Among the components comprising the vibration isolation system, air spring has become a focal point. In order to develop a complex defect tester for COG bonding of display panels, a vibration isolation system composed of air springs for mounting is considered in this study. The dynamic characteristics of the air spring are investigated, which is the most essential ingredient for reducing the vibration problem of the tester to the lowest level. Uncoupled dynamic parameters of the air spring are identified through MTS experiments, followed by suggestion of a model-based approach to obtain the remaining coupled dynamic parameters. Finally, the dynamic behaviors of the air spring are estimated and discussed.

• Journal of IKEEE
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• v.19 no.1
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• pp.18-26
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• 2015

In this paper, we proposed and evaluated the performance of an internal MIMO (Multiple Input Multiple Output) antenna for multiband operations including LTE (Long Term Evolution) 700/2300/2500. And to enhance the isolation characteristic, a parasitic element is designed and applied. The proposed single antenna has a volume of $60mm(W){\times}38mm(L)$, and the ground plane is $60mm(W){\times}100mm(L)$. The parasitic element used for enhancing the isolation of the antenna was designed with a copper on FR4 sized $60mm(W){\times}20mm(L){\times}1.6mm(H)$, and the pattern size is $60mm(W){\times}15mm(L)$. Simulated and measured results showed that LTE 700/2300/2500, DCS (Digital Cellular Service: 1710-1880MHz), K-PCS (Korea-Personal Communication Service: 1750-1870MHz), US-PCS (US-Personal Communication Service: 1850-1990MHz), WCDMA (Wideband Code Division Multiple Access: 1920-2170MHz), Wibro (2300-2390MHz), Bluetooth (2400-2483MHz), WLAN (Wireless Local Area Network: 2400-2483.5MHz), US-WiMAX (US-World interoperability for Microwave Access: 2400-2590MHz) frequency bands were covered with $S_{11}$ values less than -6dB (VSWR < 3). Simulated and measured results on $S_{21}$ at 730MHz for the firstly designed MIMO antenna showed -5.50dB and -5.65dB, respectively. When with the parasitic element at the separated ground plane to enhance the isolation performance, -10.33dB and -12.90dB are obtained for the simulation and measurement, so the enhanced isolation performance at lower frequency band (617-867MHz) is confirmed.

• Journal of the Korean Magnetics Society
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• v.9 no.1
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• pp.55-63
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• 1999

It is necessary to eliminate the broad band noise whose frequency is in the range of several kHz to tens MHz generated from the AC power line to supply the power to electrical and electronic equipments. Because this kind of noise could damage or malfunction such equipments. To suppress those noises, some conventional devices such as a filter or surge suppressor have been used. However, they can not be isolated from the common-mode noise widely spreaded in all power line, which results in poor common-mode rejection performance. In this paper, we proposed a design method of shielded isolation transformer and a jumped circuit analysis model for shielded isolation transformer applicable to filtering common-mode noise as well as normal-mode noise. The analysis model has been verified as a suitable one for shielded isolation transformer through comparison of the simulation with experiment. In addition, it has been shown that the reduction performance for conducted noise of prototype 3 kVA shielded isolation transformer is superior to a unshielded isolation transformer.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.4
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• pp.427-435
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• 2014

Segmented-channel MOSFETs (SegFETs) can achieve both good performance and variation robustness through the use of $HfO_2$ (a high-k material) to create the shallow trench isolation (STI) region and the very shallow trench isolation (VSTI) region in them. SegFETs with both an HTI region and a VSTI region (i.e., the STI region is filled with $HfO_2$, and the VSTI region is filled with $SiO_2$) can meet the device specifications for high-performance (HP) applications, whereas SegFETs with both an STI region and a VHTI region (i.e., the VSTI region is filled with $HfO_2$, and the STI region is filled with $SiO_2$) are best suited to low-standby power applications. AC analysis shows that the total capacitance of the gate ($C_{gg}$) is strongly affected by the materials in the STI and VSTI regions because of the fringing electric-field effect. This implies that the highest $C_{gg}$ value can be obtained in an HTI/VHTI SegFET. Lastly, the three-dimensional TCAD simulation results with three different random variation sources [e.g., line-edge roughness (LER), random dopant fluctuation (RDF), and work-function variation (WFV)] show that there is no significant dependence on the materials used in the STI or VSTI regions, because of the predominance of the WFV.