• 한국전기전자재료학회논문지
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• 제25권1호
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• pp.15-19
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• 2012

Presented herein are the results of the study that was conducted on the electrical characteristics of organic field-effect transistors based on poly(3-hexylthiophene), particularly the thickness and annealing temperature of their active layer is varied. The changes in field-effect mobility and current on/off ratio were explored. It was observed that both increasing annealing temperature from $60^{\circ}C$ to $100^{\circ}C$ and various concentrations influence the trade-off relations between the mobility and current on/off ratio. The surface morphology of the 2-${\mu}m^2$ area with various thicknesses was scanned via atomic-forcemicroscopy(AFM) to verify the relationship between surface morphology, which is related to the thickness of the film, and device performance.

• 한국전기전자재료학회논문지
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• 제24권5호
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• pp.364-369
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• 2011

Analyzing electrical degradation of polycrystalline silicon transistor to applicable at several environment is very important issue. In this research, after fabricating p channel poly crystalline silicon TFT (thin film transistor) electrical characteristics were compare and analized that changed by gate bias with first measurement. As a result on and off current was reduced by variation of gate bias and especially re duce ratio of off current was reduced by $7.1{\times}10^1$. On/off current ratio, threshold voltage and electron mobility increased. Also, when channel length gets shorter on/off current ratio was increased more and thresh old voltage increased less. It was cause due to electron trap and de-trap to gate silicon oxide by variation of gate bias.

• 한국전기전자재료학회논문지
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• 제22권2호
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• pp.107-113
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• 2009

In order to improve air stability, we proposed a new active layer of an organic TFT by synthesizing P3HT/POSS conjugated polymer. P3HT/POSS OTFTs with the various P3HT/POSS volume ratios were fabricated and characterized. With the P3HT/POSS volume ratio of 1:1, we achieved the field-effect mobilities of ${\sim}1.19{\times}10^{-3}\;cm^2/v{\cdot}sec$ in the saturation region and the current on/off ratio of ${\sim}2.51{\times}10^2$. The resulting current on-off ratio was much higher than that of the P3HT-based OTFTs and resulted from the dramatic decrease of the off-current. Since the off-current can be reduced by preventing oxygen in atmosphere from doping the P3HT/POSS active layers, this new active layer shows its ability to avoid oxygen doping in atmosphere. Therefore, the improvement of the air stability can be achieved by employing the P3HT/POSS active layers.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.668-673
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• 1998

The specimen of current study has the same type with the 3-span slabs of Burns et al used in the study by Mojtahedi/Gamble, which laid a ground for the revision of the ACI318-77 code to the ACI 318-83 code. But those specimens was failed prematurely before it reached the ultimate strength which the specimen had. The reason is that bonded reinforcements were cut off where there is no need for the flexural reinforcement. As results. the slabs failed ultimately where the reinforcements was cut off. Thus, the tendon stresses of failure may have been much smaller than the values which culd reach if the bonded reinforcements were extended beyond the theoretical cut off points. On the based on the fact mentioned above. the specimens which had the same conditions as the specimens of Burns et al were used in the current study, but in which the reinforcements were distributed in a sequence for the reinforcements not to be cut anywhere in the 3-span. As a results, it was known that the current ACI code, revised by the result of Mojtahedi/Gamble's study, overestimated the effect of span/depth ratio on the members with high span/depth ratio. Thus it was concluded that the effect of span/depth ratio on the ultimate stress of unbonded tendon regulated by the current ACI code must be reconsidered and reevaluated.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.560-562
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• 2009

In this paper, we proposed a simple method of decreasing the off current generated by degradation for improve the electrical characteristics such as mobility and on/off current ratio by making the line patterns on the pentacene surface between the electrodes using atomic force microscope (AFM) lithography.

• 대한전자공학회논문지SD
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• 제44권12호
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• pp.43-53
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• 2007

넓은 온도 범위에서 고정된 구동 전류로 동작하는 VCSEL(Vertical-Cavity Surface-Emitting Laser) 송신기의 저전류 동작 특성을 살펴보았다. 사용된 VCSEL은 산화형 850 nm 레이서로, $d^2I_{th}/dT^2$값이 약 $1.346\times10^{-4}mA/^{\circ}C^2$으로 문턱전류의 온도의 존성이 비교적 낮은 것이었으며, 데이터 속도는 1.25 Gbps였다. 칩 상태에서의 광출력-전류-전압을 측정하여 $20^{\circ}C$에서의 광출력이 1 mW가 되는 전류를 on 전류로 설정한 후 $-20^{\circ}C$에서 $80^{\circ}C$의 온도 범위에서 $20^{\circ}C$ 간격으로 온도를 바꾸어가며 off 전류의 변화에 따른 turn-on 특성, turn-off 특성 그리고 eye-diagram을 관찰하였고 온도와 off 전류에 따라 eye-diagram에서 rise time, fall time, extinction ratio, timing jitter가 어떻게 변화하는지를 살펴보았다. 그 결과 최소 문턱전류보다 약 $0.1\sim0.2mA$ 정도 낮게 off 전류를 설정하면 $-20^{\circ}C$에서 $80^{\circ}C$의 온도 범위에서 off 전류와 on 전류를 변화시키지 않고 1.25 Gbps에서 송신기로 동작 시킬 수 있음을 확인하였다.

• 대한전자공학회논문지TE
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• 제37권2호
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• pp.12-16
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• 2000

본 연구는 n-채널 다결정 실리콘 박막 트랜지스터를 LDD 길이에 변화를 주며 제조한 후 이에 따른 전기적인 특성을 분석하였다. LDD 구조를 갖는 소자는 LDD 영역에 의한 직렬저항 효과와 드레인 부근의 전계 감소 효과에 의해서 기존의 구조를 가지는 소자에서 볼 수 있었던 Kink 현상이 사라지게 된다. 또한, on전류의 소폭 감소와 함께 큰 폭의 off 전류 감소가 일어나 on/off 전류비가 기존 구조를 갖는 소자보다 크게 증가하게 된다. 이는 LDD 영역에 의한 직렬저항 효과보다 전계 감소 효과가 더 지배적으로 나타나기 때문으로 사료된다.

• 한국전기전자재료학회논문지
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• 제11권7호
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• pp.522-526
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• 1998

We have fabricated a LDD structured polysilicon thin film transistor with low leakge current and the optimized LDD length has been obtained. The device performance is improved is improved by hydrogen passivation process. The on.off current ratio of poly0Si TFT s with $0.5{\mu}m$ and $1.0{\mu}m$ LDD length is much higher than that of conventional structured device due to the decrease of leakege current. The optimized LDD length may be $0.5{\mu}$ from the experimental data such as on/off current ratio, threshold voltage and hydrogenation effect.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.501-506
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• 2022

Long turn-off time limits high frequency operation of Bipolar Junction Transistors (BJTs). Turn-off time decreases with increases in the recombination rate of minority carriers at switching transients. Fast neutron irradiation on a Si BJT incurs lattice damages owing to the displacement of silicon atoms. The lattice damages increase the recombination rate of injected holes with electrons, and decrease the hole lifetime in the base region of pnp Si BJT. Fast neutrons generated from a beryllium target with 30 MeV protons by an MC-50 cyclotron were irradiated onto pnp Si BJTs in experiment. The experimental results show that the turn-off time, including the storage time and fall time, decreases with increases in fast neutron fluence. Additionally, it is confirmed that the base current increases, and the collector current and base-to-collector current amplification ratio decrease due to fast neutron irradiation.

• 전자공학회논문지A
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• 제33A권3호
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• pp.96-106
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• 1996

One of the major problems for poly-Si TFTs is the large off state leakage current. LDD (lightly doped drain) and offset gated structures have been employed in order to reduce the leakage current. However, these structures also redcue the oN current significantly due to the extra series resistance caussed by the LDD or offset region. It is desirable to have a device which would have the properties of the offset gated structure in the OFF state, while behaving like a fully gated device in the oN state. Therefore, we propose a new thin film transistor with pnp junction gate which reduce the leakage curretn during the OFF state without sacrificing the ON current during the ON state.