• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.634-636
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• 2021

In this study, we studied the macro-modeling of an feedback field-effect transistor (FBFET) using SPICE simulation. The previously presented macro-model of the FBFET is consisting of two circuits. one is charge integration circuit, and the other is current generation circuit. The previous current generation circuit has problem that can't predict performance accurately of the circuits, due to implementing only I_DS-V_GS characteristics. To solve this problem, we presents a model that can implement not only I_DS-V_GS characteristics but alos I_DS-V_DS characteristics by adding the diode in the current generation circuit.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.2
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• pp.28-34
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• 2011

In previous reports, we investigated a selective assembly method of fabricating single-walled carbon nanotubes (SWCNTs) on a silicon-dioxide ($SiO_2$) surface by using only a photolithographic process. In this paper, we have fabricated field effect transistors (FETs) with SWCNT channels by using the technique mentioned above. Also, we have electrically measured gating effects of these FETs under different source-drain voltages ($V_{SD}$). These FETs have been fabricated for sensor applications. Photoresist (PR) patterns have been made on a $SiO_2$-grown silicon (Si) substrate by using a photolithographic process. This PR-patterned substrate have been dipped into a SWCNT solution dispersed in dichlorobenzene (DCB). These PR patterns have been removed by using aceton. As a result, a selectively-assembled SWCNT channels in FET arrays have been obtained between source and drain electrodes. Finally, we have successfully fabricated 4 FET arrays based on SWCNT-channels by using our simple self-assembly technique.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.475-476
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• 2019

L-shaped tunneling field-effect-transistor (LTFET) is considered a superior device over conventional TFETs. However, experimentally demonstrated LTFET demonstrated poor subthreshold characteristics which was attributed to trap-assisted-tunneling (TAT) caused by presence of trap states. In this paper, TAT mechanism in the experimentally demonstrated LTFET is investigated with the help of band diagram and TAT recombination rate (GTAT).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1489-1496
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• 2009

Amorphous indium-gallium-zinc-oxide thin-film-transistors (TFTs) were modeled successfully. Dependence of TFT characteristics on structure, thickness, and equilibrium electron-density of the active layer was studied. For mono-active-layer TFTs, a thinner active layer had higher field-effect mobility. Threshold voltage showed the smallest absolute value for the 20 nm active-layer. Subthreshold swing showed almost no dependence on active-layer thickness. For the double-active-layer case, better switching performances were obtained for TFTs with bottom active layers with higher equilibrium electron density. TFTs with thinner active layers had higher mobility. Threshold voltage shifted in the minus direction as a function of the increase in the thickness of the layer with higher equilibrium electron-density. Subthreshold swing showed almost no dependence on active-layer structure. These data will be useful in optimizing the structure, the thickness, and the doping ratio of the active layers of oxide-semiconductor TFTs.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1400-1402
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• 2002

금속유도 측면 결정화 (Metal Induced Lateral Crystallization; MILC)를 통하여 형성한 다결정 실리콘 박막에 엑시머 (excimer) 레이저를 조사하여 우수한 특성을 갖는 박막 트랜지스터를 제작하였다. MILC 공정 중에 형성되는 금속 유도 결정화 (Metal Induced Crystallization; MIC) 실리콘 박막은 다량의 Ni을 함유하고 있기 때문에, 이에 인접한 MILC 실리콘 박막 내에는 니켈 농도의 점진적인 차이가 발생한다. MILC 다결정 실리콘 박막 내의 Ni 농도 차이는 실리콘 박막의 용융점 차이를 유발하여 레이저 결정화 시에 매우 큰 실리콘 결정립의 성장을 유도한다. 새로운 다결정 실리콘 박막 트랜지스터는 기존의 레이저 결정화 방식으로 제작한 다결정 실리콘 박막 트랜지스터에 비하여 40% 향상된 전계효과 이동도를 나타내었다.

• Journal of IKEEE
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• v.27 no.4
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• pp.418-424
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• 2023

In this study, we examined the effects of annealing on electrical characteristics of double-gated silicon nanosheet (SiNS) feedback field effect transistors (FBFETs). When bias stresses were applied for 1000 s, the double-gated SiNS FBFETs were more affected by positive bias stresses than negative bias stresses regardless of the channel mode owing to the increase of interface traps caused by electrons in the inversion layers. After annealing at 300 ℃ for 10 mins, the devices were completely recovered to their original properties, and the characteristics did not change anymore when bias stresses were applied again for 1000 s.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.194-194
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• 2013

본 연구에서는 a-IGZO 활성층에 다른 dose량의 수소 이온을 조사하여 박막 트랜지스터 소자의 효과를 알아보고, 수소 이온 조사 후, 이온 조사에 따른 불안정한 소자 특성을 안정화시킬 목적으로 후 열처리에 따른 소자 특성을 알아보았다. a-IGZO 활성층에 수소이온을 110keV의 에너지로 가속하여, 수소 이온 조사량을 $1{\times}10^{14}\;ion/cm^2$, $1{\times}10^{15}\;ion/cm^2$, $1{\times}10^{16}\;ion/cm^2$로 조절하였고, 후 열처리 공정은 a-IGZO 활성층에 $1{\times}10^{16}\;ion/cm^2$ 이온조사 후, 대기 분위기로 $150^{\circ}C$, $250^{\circ}C$, $350^{\circ}C$ 각각 1시간 동안 열처리를 진행하였다. Spectroscopy Ellipsometry (SE)로 측정된 3eV이상의 광학적 밴드 갭은 기존에 보고 되었던 비정질 산화물 반도체와도 유사한 밴드 갭을 가지고 있음을 확인하였다. IGZO 박막을 활성층으로 사용하여 수소 이온 조사 공정 후 제작한 박막 트랜지스터는 3.89 $cm^2/Vs$의 전계효과이동도와 0.59V/decade의 문턱전압 이하 기울기를 보았다. 수소 이온 조사 공정을 통한 IGZO 박막 트랜지스터의 output curve가 다소 불안정함을 보였으나, $1{\times}10^{16}\;ion/cm^2$ 이온조사 후, 대기 분위기로 $150^{\circ}C$, $250^{\circ}C$, $350^{\circ}C$ 각각 1시간동안 열처리를 진행한 박막 트랜지스터의 특성은 소자의 불안정성을 보완해줄뿐만 아니라 $350^{\circ}C$ 열처리에서는 16.9 $cm^2/Vs$의 전계효과이동도와 0.33V/decade의 문턱전압 이하 기울기와 같이 더 향상된 박막 트랜지스터의 전기적 특성 결과를 관측하였다. 기존의 연구 되어진 a-IGZO 활성층에 수소이온조사와 후 열처리 공정에 따라 광학적 밴드 갭 에너지 준위의 변화와 박막 및 박막 트랜지스터 특성을 변화시킨다는 결과를 도출하였다.

• Journal of Adhesion and Interface
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• v.21 no.4
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• pp.129-134
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• 2020

Understanding charge trapping at the interface between conjugated semiconductor and polymer dielectric basically gives insight into the development of long-term stable organic field-effect transistors (OFET). Here, the charge transport properties of OFETs using polymer dielectric with various molecular weights (MWs) have been investigated. The conjugated semiconductor, pentacene exhibited morphology and crystallinity, insensitive to MWs of polymethyl methacrylate (PMMA) dielectric. Consequently, transfer curves and field-effect mobilities of as-prepared devices are independent of MWs. Under bias stress in humid environment, however, the drain current decay as well as transfer curve shift are found to increase as the MW of PMMA decreases (MW effect). The charge trapping induced by MW effect is irreversible, that is, the localized charges are difficult to be delocalized. The MW effect is caused by the variation in the density of polymer chain ends in the PMMA: the free volumes at the PMMA chain ends act as charge trap sites, corresponding to drain current decay depending on MWs of PMMA.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.240.1-240.1
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• 2005

• Electrical & Electronic Materials
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• v.16 no.6
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• pp.3-20
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• 2003