• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.50-52
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• 2006

본 논문은 고성능 다결정 실리콘(Poly-Si) 박막 트랜지스터 (Thin Film Transistor)에서 단일 수직 그레인 경계(Single Perpendlcular Grain Boundary)가 고온 캐리어 스트레스(Hot Carrier Stress) 및 정전류 안정성 평가에서 어떠한 효과를 보이는가에 대해서 살펴보았다. 고온 캐리어 스트레스 하에서($V_G=V_{TH}+1V,\;V_D$ =12V),그레이 경계가 없는 다결정 실리콘 TFT와 비교했을 때 그레인 경계를 가지고 있는 다결정 실리를 TFT는 전기 전도(Electric Conduction)에 작용하는 자유 캐리어(Free Carrier)의 개수가 적기 때문에 상대적으로 더욱 우수한 전기적 특성을 나타낸다. 먼저 1000초 동안 고온 캐리어 스트레스를 가해준 결과 단일 그레인 경계를 가진 다결정 실리콘에서의 트랜스 컨덕턴스(Transconductance)의 이동 정도는 5% 미만으로 확인되었다. 반면에 같은 스트레스 조건 하에서 그레인 경계가 존재하지 않는 다결정 실리콘의 경우에는 그 이동 정도가 약 25%에 달하는 것으로 측정되었다. 다음으로 정전류 스트레스(Constant Current Stress) 인가시, 수직형 그레인 경계가 채널 영역 내에 존재하지 않는 다결정 실리콘 TFT는 드레인 접합 부분의 전계 세기를 비교했을 때, 그레인 경계를 가지고 있는 다결정 실리콘 TFT보다 상대적으로 낮은 원 인 때문에 적게 열화되는(Degraded) 특성을 확인할 수 있었다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.162-170
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• 1996

A breakdown model of gate oxides under constant current stresses is proposed. This model directly relates the oxide lifetime to the stress current density, and includes statistical nature of oxide breakdown using the concept of "effective oxide thinning". It is shown tha this model can reliably predict the TDDB characteristics for any current stress levels and oxide areas.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.293-293
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• 2008

초전도 케이블은 저손실 대용량 전력수송이 가능한 전력케이블로서 대도시의 전력 공급문제를 해결할 수 있는 환경 친화적 신개념의 전력케이블이다. 한전 전력연구원 고창전력시험센터에서는 2006년에 22.9 kV, 100 m, 50 MVA급 초전도케이블 시스템을 설치하여 초전도케이블 실용화를 위한 신뢰성 시험을 실시하고 있다. 전력케이블의 주요한 신뢰성 요인 중의 하나가 절연특성이며 초전도케이블의 절연특성은 운전온도가 액체질소 온도이므로 절연지에 수분이 고화하여 일반적인 전력케이블보다 좋은 절연특성을 보이는 것으로 알려져 있다. 초전도 케이블은 절연지와 액체질소에 의해 절연이 이루어지며 열적, 기계적, 전기적, 환경적 스트레스에 의해 열화가 발생할 수 있다. 절연층에 이러한 스트레스가 누적되면서 void가 발생하게 되고 전계집중 현상에 의해 절연성능이 저하되며 과다한 열화의 발생시 절연파괴가 일어나게 된다. 온 발표에서는 운전온도 66.4 K에서 1.5 $U_0$ (20 kV) 전압의 30일간 연속 인가 시험과 초전도 케이블의 절연열화 가속시험을 통하여 얻은 부분방전 및 정전용량의 변화 등의 절연특성 평가 결과에 대해 논의한다.

• Journal of the Korea Society of Computer and Information
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• v.5 no.4
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• pp.102-105
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• 2000

The self-aligned AICaAs/GaAs HBTs with the mesa-etched emitter showed severe degradation in current gain under stress. The cause was identified to be due to instability of the surface states on extrinsic base. In this paper the surface states were diminished by the hetero-passivation of the InGaP ledge emitter and the reliability was drastically improved. The activation energy of current gain degradation was extracted to be 1.97eV and MTTF to be 4.8$\times$108 at 14$0^{\circ}C$ which has satisfied MIL standards.

• Electrical & Electronic Materials
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• v.7 no.1
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• pp.25-31
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• 1994

Properties of oxynitride films reoxidized by $N_2{O}$ gas after thermal oxidation and $N_2{O}$ oxide films directly oxidized by using $N_2{O}$ gas on the bare silicon wafer have been studied. From the AES analysis, nitrogen pile-up at the interface of Si/oxynitride and Si/$N_2{O}$ oxide has observed. $N_2{O}$ oxide and oxynitride films have the self-limited characteristics. Therefore, it will be possible to obtain ultra-thin films. Nitrogen pile-up at the interfaces of Si/oxynitride and Si/$N_2{O}$ oxide strengthens film structure and improves dielectric reliability. Although fixed charge densities and interface trap densities of N20 oxide and oxynitride films have somewhat higher than those of thermal $SiO_2{O}$, $N_2{O}$ oxide and oxynitride films showed improved I-V characteristics and constant current stress.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.297-305
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• 2000

It is observed that the initial properties and degradation characteristics on plasma of n/p-MOSFET with polycide and poly-Si as different gate materials under F-N stress and hot electron stress are affected by metal AR(Antenna Ratio) during plasma process. Compared to that of MOS devices with poly-Si gate material, reliability properties on plasma of MOS devices with polycide gate material are improved. This can be explained by that fluorine of tungsten polycide process diffuses through poly-Si into gate oxide and results in additional oxide thickness. The fact that MOS devices with polycide gate material can reduce damages of plasma process shows possibility that polycide gate material can be used as gate material for next generation MOS devices.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.5
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• pp.52-59
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• 1989

The reliability of the thin thermal oxide was investigated by using constant current stress method. Polysilicon gate MOS capacitors with oxide thickness range of 20-25nm were used in this experiment. Automatic measurement and statistical data analysis which were essential in reliability evaluation of VLSI process preformed by HP 9000 computer. Based on TDDB results, defect density, breakdown charge (Qbd) and lifetime of oxide film were evaluated. According to the polarity of the stress, some different characteristics were shown. Defect density was 62/$cm^2$ at negative gate injection. The value of Qbd was about 30C/$cm^2$ at positive gate injection, and about 21C/$cm^2$ at negative. The current density acceleration factor was 1.43$cm^2$/A for negative gate injection, and 1.25$cm^2$/A for positive gate injection.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.10
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• pp.1-8
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• 1999

In this paper, we have studies the transport mechanism and origin of SILC for the various thickness of wet oxide. Also, SILC characteristics of $N_2O$ annealed oxide was included in this study. We made the flash memory cell with $N_2O$ annealed oxide of 60Athick under $0.25{\mu}m$ design rule, and measured the characteristics of the cell. As a result, we have found that the origin of SILC is due to the trap formed inside of the oxide layer by electrical stress. And we reached the conclusion that the transport mechanism of SILC is ruled by the modified F-N tunneling if the electric field is lower than 8MV/cm or typical F-N tunneling if the electric field is higher than 8MV/cm. We could also confirm the fact that $N_2O$ annealed oxide of 60Athick have an improved resistance effect against SILC. In case that we apply $N_2O$ annealed oxide of 60Athick to the flash memory, we could confirm $10^6$ times endurance and more than 10 years drain disturb, and could get 8V programmable flash memory characteristics.