• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.2
• /
• pp.117-122
• /
• 2016

Recently, the detection of pH with real-time and in vivo has been focal pointed in the environmental or medical fields. In this work, we developed the pH sensor using graphene sheet. Graphene has high biocompatibility. We fabricated flexible solution-gated field-effect transistors (SGFETs) on graphene sheet transferred on the polyethylene terephthalate (PET) substrate to detect pH in electrolyte solution. The gate length was $500{\mu}m$ and the gate width was 8 mm. We evaluated the current-voltage (I-V) transfer characteristics of graphene SGFETs in pH solution. The drain-source current ($I_{DS}$) and the gate-source voltage ($V_{GS}$) curves of graphene SGFETs were depended on pH value. The Dirac point of graphene SGFETs linearly shifted to the positive direction about 19.32 mV/pH depending on the pH value in electrolyte solution.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.8 no.2
• /
• pp.156-163
• /
• 2008

We proposed a new $p^+/n^+$ gate locally-separated-channel (LSC) bulk FinFET which has vertically formed oxide region in the center of fin body, and device characteristics were optimized and compared with that of normal channel (NC) FinFET. Key device characteristics were investigated by changing length of $n^+$ poly-Si gate ($L_s$), the material filling the trench, and the width and length of the trench at a given gate length ($L_g$). Using 3-dimensional simulations, we confirmed that short-channel effects were properly suppressed although the fin width was the same as that of NC device. The LSC device having the trench non-overlapped with the source/drain diffusion region showed excellent $I_{off}$ suitable for sub-50 nm DRAM cell transistors. Design of the LSC devices were performed to get reasonable $L_s/L_g$ and channel fin width ($W_{cfin}$) at given $L_gs$ of 30 nm, 40 nm, and 50 nm.

• Electronics and Telecommunications Trends
• /
• v.24 no.2
• /
• pp.84-96
• /
• 2009

유럽연합은 1990년대에 접어들면서 미국과의 경제 격차가 점차 확대되자 미국을 따라잡기 위해 리스본 전략을 채택하였다. 이 전략의 목표는 유럽의 정보화를 통한 성장, 고용, 사회적 참여로 요약할 수 있다. 리스본 전략에서 제시된 정보화 모토는 정책과 연구개발을 2개의 기둥으로 하고, 이 두 영역간의 긴밀한 상호협조를 통해 유럽정보화의 시너지를 창출하자는 것이었다. 정책 부문은 리스본 전략에서 출발하여 신 리스본 전략, i2010 전략으로 발전되어 왔으며, 이에 맞추어 연구개발 부문은 FP5, FP6으로 발전되어 오다가 현재는 FP7이 시행되고 있다. 본 고에서는 FP7의 ICT 연구프로그램에서 제안하는 도전과제와 미래기술전략을 소개하는 한편, 그 정책적 시사점을 도출하였다. FP7 ICT 연구프로그램은 유럽이 차세대 ICT 및 그 사용에 있어서 세계 선도 그룹에 들기 위해 극복해야 할 7가지 도전과제를 제안하고 있다. 이들 도전 과제들은 크게 업계의 기술 목표 및 사회경제적 목표 달성을 위한 과제로 이분할 수 있으며, 향후 10년 간의 목표와 성과물을 제시하고 있다. FP7 ICT 연구프로그램 중 '미래 및 새로 부상하고 있는 기술(FET)' 프로젝트는 예상하지 못했던 아이디어와 발전에 효과적으로 대응하기 위하여 '개방형 FET프로젝트'와 '전 방위적 FET 프로젝트'의 두 가지 상호보완적 플랜을 운영하고 있다. 본 고에서는 이들 프로젝트에 대하여 성과목표, 기대효과, 자금지원 및 예산분배계획을 간략하게 소개하였다. 결론부에서는 앞에서의 논의를 토대로 우리나라의 미래 ICT 기술개발 전략 구상시 참조해야 할 정책적 시사점을 제시하였다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.500-500
• /
• 2011

With recent advances in flexible and stretchable electronics, the development of physically responsive field-effect transistors (physi-FETs) that are easily integrated with transformable substrates may enable the omnipresence of physical sensing devices in electronic gadgets. However, physical stimuli typically induce whole sensing physi-FET devices under global influences that also cause changes in the parameters of FET transducers, such as channel mobility and dielectric capacitance that prevent proper interpretations of response in sensing materials. Extended-gate structures with isolated stimuli have been used recently in physi-FETs to demonstrate performances of sensing materials only. However, such approaches are limited to prototype researches since isolated stimuli rarely occur in real-life applications. In this report, we theoretically and experimentally demonstrated that integrating piezoelectric nanocomposites directly into flexible organic FETs (OFETs) as gate dielectrics provides a general research direction to physi-FETs with a simple device structure and the capability of precisely investigating functional materials. Measurements with static stimulations, which cannot be performed in conventional systems, exhibited giant-positive d33 values of nanocomposites of barium titanate (BT) NPs and poly (vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.14 no.11
• /
• pp.912-916
• /
• 2001

Fluxmeter is a measuring instrument the magnetic flux intensity by means of an integration of the voltage induced to a search coil to unit time. It also is required to a precise integrator since the voltage induced to a search coil has a differential value of the flux ${\Phi}$ to unit time. In this study, a bias current which is a main problem of the integrator in a drift troublesome depending on the temperature of a FET is investigated. We have confirmed that the temperature dependence of both the bias current of a integrator using the FET and the reversal saturated current of the minor carrier in a P-N junction of a semiconductor were the same. The property of a commercial integrator goes rapidly down with increasing temperature. The bias current of a FET is increased twice as much with 10$^{\circ}C$ increment. As a result, the low drift integrator could be developed by setting the lower temperature up with a pottier device.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.42 no.7 s.337
• /
• pp.57-62
• /
• 2005

This paper describes the design of a high performance microwave single pole double throw (SPDT) monolithic microwave integrated circuit switch using GaAs pHEMT process. The switch design proposes a novel coplanar waveguide (CPW) impedance transform network which results in the low insertion loss and high isolation by compensating for the FET parasitics to get the low on-resistance and low off-capacitance. The proposed switch has the measured isolation of better than 24 dB and insertion loss of less than 2.6 dB from 53 to 61 GHz. The chip is fabricated with the size of 2.2mm $\times$ 1.6 mm.

• Current Applied Physics
• /
• v.18 no.12
• /
• pp.1546-1552
• /
• 2018

The polymer nanocomposite as a gate dielectric film was prepared via sol-gel method. The formation of crosslinked structure among nanofillers and polymer matrix was proved by Fourier transform infrared spectroscopy (FT-IR). Differential thermal analysis (DTA) results showed significant increase in the thermal stability of the nanocomposite with respect to that of pure polymer. The nanocomposite films deposited on the p- and n-type Si substrates formed very smooth surface with rms roughness of 0.045 and 0.058 nm respectively. Deconvoluted $Si_{2s}$ spectra revealed the domination of the Si-OH hydrogen bonds and Si-O-Si covalence bonds in the structure of the nanocomposite film deposited on the p- and n-type Si semiconductor layers respectively. The fabricated n-channel field-effect-transistor (FET) showed the low threshold voltage and leakage currents because of the stronger connection between the nanocomposite and n-type Si substrate. Whereas, dominated hydroxyl groups in the nanocomposite dielectric film deposited on the p-type Si substrate increased trap states in the interface, led to the drop of FET operation.

• Clinical and Experimental Reproductive Medicine
• /
• v.42 no.4
• /
• pp.175-180
• /
• 2015

Objective: Embryo loading (EL) is a major step in embryo transfer (ET) and affect on the success of in vitro fertilization (IVF). This study aimed to compare the effect of two different EL techniques on the rates of pregnancy and delivery in IVF/ET cycles. Methods: 207 fresh ET and 194 Frozen-thawed ET (FET) cycles were included in this retrospective study. Two groups (A and B) were defined based on the EL technique used. In group A, the entire catheter was flushed with Ham's F-10 medium. The embryos were then drawn into the catheter using one air bracket. In group B, $70{\mu}L$ of air was aspirated into the syringe and the catheter was flushed using Ham's F10 medium. The medium, air, embryos, air, and finally another layer of medium were then sequentially drawn into the catheter. The main outcome measures were the pregnancy and delivery rates. Results: The groups did not differ with respect to the etiology of infertility, the source of spermatozoa, the quality of the embryos, the type of EL catheter, and the ease of transfer. The pregnancy rate was similar between two groups. In fresh ET cycles, a higher delivery rate was observed in group B than it group A (78.1% vs. 60%, p=0.1). In FET cycles, the rate of delivery was significantly higher in group B than in group A to a nonsignificant extent (88.9% vs. 58.8%, p=0.06). Conclusion: EL techniques did not have a significant impact on the delivery rate in either fresh or FET cycles.

• Proceeding of EDISON Challenge
• /
• 2013.04a
• /
• pp.246-249
• /
• 2013

EDISON 나노물리 사이트에 탑재된 탄소나노튜브 FET 소자 시뮬레이션 툴을 이용하여 나노 CNT 소자에서의 p-n접합이 갖는 특성을 살펴보았다. 순방향 바이어스에서는 일반적인 p-n접합과 유사한 특성을 보이나 그 원리는 다름을 알 수 있었으며, 역방향 바이어스에서는 밴드 대 밴드 터널링에 의한 전류가 발생함을 확인하였다. 또한 이러한 역방향 바이어스 하의 전류가 도핑농도에 따라 변함을 확인하여 실제 CNT 소자의 도핑농도를 예측해볼 수 있는 가능성을 확인하였다.

• Journal of Sensor Science and Technology
• /
• v.9 no.2
• /
• pp.106-112
• /
• 2000

A FET-type reference electrode(REFET) is an effective method to eliminate typical problems with ISFET(ion sensitive field-effect transistor) such as drift, temperature, light-dependence and miniaturization of reference electrode. However, it is difficult to make the highly reliable REFET with excellent long-term stability and reproducibility. In this paper, an ion-blocking membrane was applied to the REFET for the PET-type electrolyte sensors(pH, pNa-ISFET). The fabricated REFET indicated the stable sensitivity (55.4 mV/pH, 53.5 mV/decade) and good linearity in the pH and pNa measurement. In the measurement, ISFET/Pt/REFET configuration showed excellent stability and reproducibility.