• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.4
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• pp.325-329
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• 2013

Carbon nanotubes(CNT) have excellent electrical, chemical stability and mechanical properties. These can be used in a variety of fields. MWCNT are extremely sensitive for minute changes in the ambient gas, namely, their sensing properties varies greatly with the absorption of gas such as NOx and $H_2$. We investigate the electrical properties of CNTs and make a NOx gas sensor based on Multi-walled carbon nanotubes (MWCNT) materials. We obtained the NOx gas sensor of MWCNT based on P-type Si wafer that has the resistivity of $1.667{\times}10^{-1}[{\Omega}{\cdot}cm]$. We knew that the sensitivity of sensor decreased with increasing of NOx gas concentration. And the sensitivity of sensor shows the largest value at $20^{\circ}C$. The sensitivity of sensor decrease with increasing the temperature. Also absorption energy of NOx gas molecule on the MWCNT surface decreases with increasing concentration of NOx gas.

• Journal of Sensor Science and Technology
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• v.10 no.3
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• pp.180-186
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• 2001

Recently, FET type dissolved oxygen sensor was proposed to overcome the disadvantages of the amperometric Clark-type sensor. The inherent problem of the proposed sensor, however, is the flow dependence of the sensor performances since the proposed sensor detects the pH change in close proximity to the working electrode. In this study, we decided the direction which minimize the flow effect in FIA(flow injection analysis) system. And a hydrodynamic buffer layer which can reduce the flow dependence were proposed. The suggested buffer-layers were formed onto sensing area and working electrode with mixed polymer matrix of TEOS(tetraethylorthosilicate) and DEDMS(diethoxydimethylsilane).

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.6
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• pp.585-593
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• 2015

In the nanoscale regime, many multigate devices are explored to reduce their size further and to enhance their performance. In this paper, design of a novel device called, Triple Material Surrounding Gate Tunnel Field effect transistor (TMSGTFET) has been developed and proposed. The advantages of surrounding gate and tunnel FET are combined to form a new structure. The gate material surrounding the device is replaced by three gate materials of different work functions in order to curb the short channel effects. A 2-D analytical modeling of the surface potential, lateral electric field, vertical electric field and drain current of the device is done, and the results are discussed. A step up potential profile is obtained which screens the drain potential, thus reducing the drain control over the channel. This results in appreciable diminishing of short channel effects and hot carrier effects. The proposed model also shows improved ON current. The excellent device characteristics predicted by the model are validated using TCAD simulation, thus ensuring the accuracy of our model.

• Development and Reproduction
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• v.22 no.1
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• pp.105-109
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• 2018

A 40-year-old G1 P0 L0 A1 woman was referred to our clinic with 6-year history of infertility. Before visiting the clinic, she had 3 cycles of In-Vitro Fertilization (IVF) procedures (2 cycles of Controlled Ovarian Stimulation-IVF and 1 cycle of frozen-thawed Embryo Transfer (ET)) at other clinic. She had medical history of abortion at early gestation following FET (frozen-thawed-ET). The patient had complete type of septate uterus, double cervix and longitudinal vaginal septum. Vaginal septotomy was done first and 1 month later, hysteroscopic septoplasty was followed using ballooning filled with dye. After septoplasty, we inserted ballooning and left for several days to compress septal endometrium on the septectomy area. All procedures were done in the ambulatory operating room without laparoscopy or admission. 3 months later, she had in vitro fertilization-embryo transfer (IVF-ET) and FET procedures in our clinic. She had successful pregnancy and now is at 22 weeks of gestation. New ambulatory septoplasty using dye-filled ballooning is easy, safe and minimally invasive surgery for treatment of complete septate uterus.

• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.7-11
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• 2014

In this paper, we designed resistive MMIC mixer using $0.5{\mu}m$ p-HEMT process. This Mixer is designed to have a similar performance in -4 ~ 4 dBm local oscillator signal power level and to maintain a constant conversion loss and linear performance due to the variation of local signal. In order to have such characteristics, we designed new feedback circuit topology by using FET, and minimized performance change for LO signal power level variation, also obtain MMIC mixer characteristics which is able to apply in wideband. In the design result, When the LO signal power is -4 ~ 4 dBm, there was 6 dB conversion loss and it came up with the excellent result that IIP3 got over 30 dBm in 0.5 ~ 2.6GHz frequency band.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.342-345
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• 2009

Bright light-emitting single crystal organic field-effect transistors (FETs) based on highly luminescent oligo(p-phenylenevinylene) (OPV) derivatives are demonstrated. Although OPV single crystal FETs show both p - and n - type FET operation, we found that an increase in the conjugation length of the OPV derivatives from three phenylene rings to five phenylene rings results in an improvement in the electron mobility by an order of magnitude, while retaining the high hole mobility with intense electroluminescence.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.988-994
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• 1986

We present an automated CMOS standard cell design mehtodology which generates a mask description in the CIF (Caltech Intermediate Form)from a user-given logic description and design rule. The resultant layout reflects the user's choice among N-well, P-well and twin-well process and user's decision whether the guard band is to be included or not. Noise margin of each cell was improved by carefully adjusting the channel width of P-FET.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1193-1203
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• 2008

An active antenna(AA) can have wider bandwidth and more gain with small antenna size than those of passive antennas. However, AA inherently generates thermal noise and spurious signals from an active device. Moreover, the spurious performance of AA is very important in a highly sensitive receiving system since it is located at the front end of the receiving system. In this study, we developed an AA with $100{\sim}500\;MHz$, having the output P1dB higher than 3 dBm and little spurious signals in real environments. To achieve such performance, we designed an AA with 3-stage amplifier using CD(common drain) FET and 2 BJTs. Its electrical performances were simulated using ADS. The measurement results for typical gain, NF, OIP3, VSWR and P1dB in the required frequency band were 9.7 dBi, 10 dB, 14 dBm, 1.7:1 and 3 dBm respectively. They are in good agreement with simulation results. The unwanted spectrum level of the proposed AA is $10{\sim}30\;dB$ lower than that of the antenna with CS(common source) FET configuration at a west suburban area of Seoul, which shows that the proposed AA can be applicable to a highly sensitive receiving system for detecting unknown weak signals mixed with broadcasting and civilian communication signals.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.413-417
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• 2023

Gallium Oxide (Ga₂O₃) is preferred as a material for next generation power semiconductors. The Ga₂O₃ should solve the disadvantages of low thermal resistance characteristics and difficulty in forming an inversion layer through p-type ion implantation. However, Ga₂O₃ is difficult to inject p-type ions, so it is being studied in a heterojunction structure using p-type oxides, such as NiO, SnO, and Cu₂O. Research the lateral-type FET structure of NiO/Ga₂O₃ heterojunction under the Gate contact using the Sentaurus TCAD simulation. At this time, the VG-ID and VD-ID curves were identified by the thickness of the Epi-region (channel) and the doping concentration of NiO of 1×10¹⁷ to 1×10¹⁹ cm-3. The increase in Epi region thickness has a lower threshold voltage from -4.4 V to -9.3 V at I_D = 1×10^-8 mA/mm, as current does not flow only when the depletion of the PN junction extends to the Epi/Sub interface. As an increase of NiO doping concentration, increases the depletion area in Ga₂O₃ region and a high electric field distribution on PN junction, and thus the breakdown voltage increases from 512 V to 636 V at I_D =1×10^-3 A/mm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.635-641
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• 1998

This paper presents development of a small size LNA operating at 824 ∼ 849 MHz used for a receiver of a CELLULAR CDMA Base station and a transponder. Using resistive decoupling circuits, a signal at low frequency is dissipated by a resistor. This design method increases the stability of the LNA and is suitable for input stage matching. The LNA consists of low noise GaAs FET ATF-10136 and internally matched VNA-25. The LNA is fabricated with both the RF circuit and the self-bias circuits in aluminum housing. As a result, the characteristics of the LNA implemented here shows above 35dB in gain and below 0.9dB in noise figure, 18.6dBm P1dB power, a typical two tone IM3, -31.17dB with single carrier backed off 10dB from P1dB.