• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.2
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• pp.74-79
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• 2003

The method of the analysis of the base Gummel number of the BJT(Bipolar Junction Transistor) for integrated circuits based upon the semiconductor physics is proposed and the method of calculating the doping profile of the base region using process conditions is presented. The transistor saturation current obtained from the proposed method of NPN BJT using 20V and 30V process shows an averaged relative error of 6.7% compared with the measured data and the transistor saturation current of PNP BJT shows an averaged relative error of 9.2% compared with the measured data

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.2
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• pp.67-73
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• 2003

The algorithm (or calculating the base-collector breakdown voltage of NPN BJT(Bipolar Junction Transistor) for integrated circuits is Proposed. The method for calculating the electric field using the solution of Poisson's equation is presented and the method for calculating the breakdown voltage using the integration of ionization coefficients is presented. The base-collector breakdown voltage of NPN BJT using 20V process obtained from the proposed method shows an averaged relative error of 8.0% compared with the measured data and the base-collector breakdown voltage of NPN BJT using 30V process shows an averaged relative error of 4.3% compared with the measured data

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.1
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• pp.33-41
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• 2003

In this work, process optimization techniques for high frequency performance of HBTs are presented. The techniques are focused on reducing parasitic base resistance and base-collector capacitance, which are key elements determining the high frequency characteristics of HBTs. Several fabrication techniques, which can significantly reduce the parasitic elements of the HBTs for improved high frequency performance, are proposed and verified by the measured data of the fabricated devices.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.164-171
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• 1996

We report the experimental resutls on AlGaAs/GaAs heterojunction bipolar transistors (HBTs) with carbon-doped base structure. To characterize the output power, load-pull mehtod was employed. By characterizing the devices with HP8510C, we extracted the small-signal equivalent circuit. The HBTs were fabricated employing wet mesa etching and lift-off process of ohmic metals. the implementation of polyimide into the fabriction process was accomplished to obtain the lower dielectric constant resultig in significant reduction of interconnect routing capacitance. The fabricated HBTs with an emitter area of 6${\times}14{\mu}m^{2}$ exhibited current gain of 45, BV$_{CEO}$ of 10V, cut-off frequency of 30GHz and power gain of 1 3dBm. To extract the small signal equivalent circuit, the de-embedded method was applied for parasitic parameters and the calculation of circuit equations for intrinsic parameters.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.9
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• pp.743-751
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• 1991

This paper presents the 1.5\ulcorner PSA bipolar device which establishes the performance improvement such as the reduction of emitter resistance and substrate junction capacitance. To achieve the above electrical characteristics, RTA process and trench isolation technology were adapted. The emitter resistance and substrate capacitance of npn transistor having 1.5$[\times}6{\mu}m^{2}$emitter area was measured with 63$\Omega$and 28fF, respectively. The minimum propagation delay time shows 121ps at 0.7mW from the measurement of 31 stage ring oscillator.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.1
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• pp.13-16
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• 2000

Progress in Si crystal and wafer technologies is discussed on single crystal growth, wafer fabrication, epitaxial growth, gettering, 300 mm and SOI. As for bulk crystal growth, the mechanism of grown-in defects (voids) formation, the succes of grown-in defect free crystal growth technology and nitrogen doped crystal are shown. New wafer fabrication technologies such as both-side mirror polishing and etchingless process have been developed. The epitaxial growth of SiGe/Si heterostructure for high speed bipolar device is treated. Gettering technology under low temperature process such as RTP is important, and also it is shown that IG effect for Ni could be predicted using computer simulation of precipitate density and size. The development of 300 mm wafer and SOI has made progress steadily.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.141-144
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• 2002

The method of the analysis of the base Gummel number of the PNP BJT(Bipolar Junction Transistor) for integrated circuits based upon the semiconductor physics is proposed and the method of calculating the doping profile of the base region using process conditions is presented. The transistor saturation current obtained from the proposed method of PNP BJT using 20V and 30V process shows an averaged relative error of 6.7% compared with the measured data.

• Transactions of Materials Processing
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• v.21 no.6
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• pp.341-347
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• 2012

The metallic bipolar plates of the molten carbonate fuel cell(MCFC) are composed of shielded slot plates and a center-plate. The shielded slot plates support the center-plate and the membrane electrode assembly. Compressive forces are applied to the shielded slot plate in order to increase the contact area between shielded slot plates and the membrane electrode assembly (MEA). In the design of the shielded slot plate, it is necessary to predict the mechanical behavior of the shielded slot plate. The shielded slot plates are manufactured by a three-stage forming process consisting of slitting, preforming and the final forming process. The mechanical behavior of the shielded slot plate is largely affected by the forming process. In this study, the simulation of the three-stage forming process was used to predict the mechanical behavior of the shielded slot plate. The present simulation approach showed good agreements with the experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.9
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• pp.45-51
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• 2014

This work carried out for the effective synthesis characteristics of graphene nanowall film by controlling the electric field in a RF plasma CVD process. For that, the bipolar bias voltage was applied to the substrate such as Si and glass materials for the best chemical reaction of positive and negative charges existing in the plasma. For supplying the seed formation sites on substrate and removing the oxidation layer on the substrate surface, the electron bombardment into substrates was performed by a positive few voltage in hydrogen plasma. After that, hydrocarbon film, which is not a graphene nanowall, was deposited on substrates under a negative bias voltage with hydrogen and methane gases. At this step, the film on substrates could not easily identify due to its transparent characteristics. However, the transparent film was easily changed into graphene nanowall by the final hydrogen plasma treatment process. The resultant raman spectra shows the existence of significant large 2D peaks corresponding to the graphene.

• Journal of the Korean institute of surface engineering
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• v.45 no.5
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• pp.206-211
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• 2012

Process analysis was carried out during deposition of MgO by inductively coupled plasma assisted reactive magnetron sputtering in Ar and $O_2$ ambient. At the initiation of Mg sputtering with bipolar pulsed dc power in Ar ambient, total pressure showed sharp increase and then slow fall. To analyse partial pressure change, QMS was used in downstream region, where the total pressure was maintained as low as $10^{-5}$ Torr during plasma processing, good for ion source and quadrupole operation. At base pressure, the major impurity was $H_2O$ and the second major impurity was $CO/N_2$ about 10%. During sputtering of Mg in Ar, $H_2$ soared up to 10.7% of Ar and remained as the major impurity during all the later process time. When $O_2$ was mixed with Ar, the partial pressure of Ar decreased in proportion to $O_2$ flow rate and that of $H_2$ dropped down to 2%. It was understood as Mg target surface was oxidized to stop $H_2$ emission by Ar ion sputtering. With ICP turned on, the major impurity $H_2$ was converted into $H_2O$ consuming $O_2$ and C was also oxidized to evolve CO and $CO_2$.