• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.3
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• pp.153-163
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• 1986

GaAs, one of the III-V compounding semicondnctors, has been widely employed as base materials for the fabrication of the ultra-high-speed devices in the filelds of DBS, optical communications, MMIC'S and digital IC'S. There have been some reports on 4Kx4bit SRAM by D/E MESFET'S, 4K bit SRAM by HEMT'S, and receiver front ends for X-band by MMIC technologies, respectively. This paper reviews GaAs materials, wafer fabrication processes, device applications, and design aspects, and, finally, descusses the future of the ultra-high-spped-devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.5
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• pp.431-438
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• 2005

In this paper, we propose the built-in current testing circuit for improving reliability As the integrated CMOS circuits in a chip are increased, the testability on design and fabrication should be considered to reduce the cost of testing and to guarantee the reliability In addition, the high degree of integration makes more failures which are different from conventional static failures and introduced by the short between transistor nodes and the bridging fault. The proposed built-in current testing method is useful for detecting not only these failures but also low current level failures and faster than conventional method. In normal mode, the detecting circuit is turned off to eliminate the degradation of CUT(Circuits Under Testing). The differential input stage in detecting circuit prevents the degradation of CUT in test mode. It is expected that this circuit improves the quality of semiconductor products, the reliability and the testability.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.735-737
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• 2003

A superconducting motor consisting of high temperature superconducting (HTS) rotor and air-core stator is under development in Korea Electrotechnology Research Institute. HTS motor was designed for having the rated power of 100hp at 1800 rpm. HTS field winding is composed of sixteen HTS race track shaped coils wound with stainless steel-reinforced Bi-2223 tape conductor by react and wind fabrication method. Nomex Paper was used for electrical insulation. Each of four magnet pole assemblies was constructed with four double pancake sub-coils, mechanically stacked and electrically in series. Four magnet assemblies were fixed on an aluminum support structure to make effective heat transfer. Critical current (Ic) of HTS field winding was 41A but minimum Ic of sub-coils was 35A at 77K and self field. Joule heat generated in HTS field winding was 2.11W at 77K and 35A.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.411-414
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• 2004

This paper introduces a modulation method for digital wireless communication based on general DS-QPSK. The design and fabrication is for home networking application to a typical RF transmitter with DS-QPSK modulator. This modulator implemented using VHDL hardware programming language, the fabrication of IC chip $5{\times}5 mm^2$ was carried by 27th IDEC MPW(Multi Project Wafer) process in 0.35${\mu}m$ rule at Samsung Inc. This paper presented the important of this technology for the future application in wireless sensor. This module can be efficient usage for home network to transmit the RF wireless sensor system.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.747-753
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• 1986

This paper describes the design and fabrication of a digital volume control integrated circuit which replaces a mechanical volume control. The integrated circuit can be controlled volume by up/down switch. It has been fabricated by SST bipolar standard process. Its chip size is 2.5x2.5 mm\ulcorner As a result, we succeeded in fabrication of integrated circuit which satisfied DC characteristics and proper operation of volume control.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.154-161
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• 2009

Recently, as many functional blocks are integrated on a small area the high speed integrated circuits emerge as a critical electromagnetic interferer which causes mal-function of adjacent circuitries and lowers the sensitivity of the wireless receivers. Therefore, it is necessary to devise an precise analyzing tool to pinpoint the major electromagnetic noise contributor among the internal circuit blocks of high speed IC's. This paper presents the design, fabrication, and measurement results of the high resolution magnetic field probe which can measure the current density on the IC surface. In order to achieve the high resolution, the magnetic field probe is fabricated using 3-metal semiconductor process so that its thickness is reduced by 10% than that of conventional works. Through the magnetostatic analysis and EM simulation, spatial resolution and sensitivity to the nonmagnetic field components are analyzed. Experimentally, it is found that the fabricated probe can measure the current density on the IC surface with $210{\mu}m$-spatial-resolution.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.695-697
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• 2013

In this paper, temperature sensing circuit using by MOS is proposed. It produces the voltage as output and is applicable for the internal IC temperature measurement. It is designed by two current mirrors using MOS to implement the IC in the CMOS fabrication and is applicable for the various applications. It operates in two mode, temperature mode and sleep mode. From the simulation results, output voltage is measured from 0V to 1.2V by sweeping $0^{\circ}C{\sim}125^{\circ}C$ in temperature mode and output current flows under 100pA in sleep mode.

• Journal of the Korean Ceramic Society
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• v.33 no.4
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• pp.471-477
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• 1996

During Bi(Pb)-Sr-Ca-Cu-O superconductor wire fabrication the effect of the initial packing density on the final characteristics of superconductor wire was systematically studied. To increase the powder packing density with uniform distribution of superconducting core a billet insertion method processed by CIP was applied instead of the commonly used vibration and ramming method of powder insertion into silver sheath. Compared with the vibration and ramming method the billent insertion technique processed by CIP cause the 30% incre-specimen with 130${\mu}{\textrm}{m}$(core thickness : 45 ${\mu}{\textrm}{m}$)and 5.24 mm width processed at 84$0^{\circ}C$for 200hrs. shows specimen with 130${\mu}{\textrm}{m}$ (core thickness ; 45${\mu}{\textrm}{m}$)and 5.24 mm width processed at 84$0^{\circ}C$ for 200 hrs. shows maximum 34A for Ic and 16, 700 A/cm2 for Ic measured at 77K and 0T. Also the sample rolled 3 times shows maximum 7, 2A for Ic and 11, 000 A/cm2 for 77K and 0T. Based on X-ray experimental results the formation of Bi-2223 and texture were significantly well developed at the interface between the superconducting core and silver sheath as compared with those of the interior area of superconducting core.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.387-390
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• 1998

In this paper, HBT's with lower phase noise and passive elements, such as resistors, capacitors and inductors, for resonance and impedance matching networks are designed, fabricated, tested, and carefully analysed, respectively, and then, they are integrated for the design and fabrication of functional X-band oscillators with lower phase noise. Epi-wafers for HBT's with the structure of graded $Al_{x}$G $a_{1-x}$ As emitter and C-doped base layer of 700.angs. thick were used to specially emphasize the improvement of $f_{T}$ and $f_{max}$, and the lowering of phase noise, in design aspects. At the test frequencies of 12GHz, capacitances of MIM capacitors, spiral inductor, and resistances are 0.5~10pF, 0.4~11.06nH, and 20~1,380.ohm., respectively. The emitter size of HBY's for the X-band MMIC oscillators is 3*10u $m^{2}$, and find chip size is 0.9*0.9m $m^{2}$..EX>.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.3
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• pp.1-7
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• 1999

A single RF transceiver evaluation board have been developed for the purpose of application to the 900MHz band transceiver contained RF-IC chip And environment test was evaluated. The RF-IC chipset includes LNA(Low Noise Amplifier), down-conversion mixer, AGC(Automatic Gain Controller), switched capacitor filter and down sampling mixer. The RF evaluation board for the testing of chipset contained various external matching circuits, filters such as RF/IF SAW(Surface Acoustic Wave) filter and duplexer and power supply circuits. With the range of 2.7~3.3V the operated chip revealed moderate power consumption of 42mA. The chip was well operated at the receiving frequency of 925~960MHz. Measurement result is similar to general RF receiving specification of the 900MHz digital mobile phone.