• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
• /
• pp.213-216
• /
• 2001

The use of a thin film of indium between the ITO and the $n^{+}$-InP contact layers for InP/InGaAs HPTs was studied without degrading its excellent optical transmittance properties. ITO/$n^{+}$-InP ohmic contact was successfully achieved by the deposition of Indium and thermal annealing. The specific contact resistance of about 6.6$\times$$10^{-4}$$\Omega\textrm{cm}^2$ was measured by use of the transmission line method (TLM). However, as the thermal annealing was just performed to ITO/$n^{+}$-InP contact without the deposition of Indium between ITO and $n^{+}$-InP, it exhibited schottky characteristics. In the applications, the DC characteristics of InP/InGaAs HPTs with ITO emitter contacts was compared with that of InP/InGaAs HBTs with the opaque emitter contacts.

• 한국전기전자재료학회논문지
• /
• 제21권11호
• /
• pp.968-972
• /
• 2008

Ni/Ti/Al multilayer system ('/'denotes the deposition sequence) was tested for low-resistance ohmic contact formation to Al-implanted p-type 4H-SiC. Ni 30 nm / Ti 50 nm / Al 300 nm layers were sequentially deposited by e-beam evaporation on the 4H-SiC samples which were implanted with Al (norminal doping concentration = $4\times10^{19}cm^{-3}$) and then annealed at $1700^{\circ}C$ for dopant activation. Rapid thermal anneal (RTA) temperature for ohmic contact formation was varied in the range of $840\sim930^{\circ}C$. Specific contact resistances were extracted from the measured current vs. voltage (I-V) data of linear- and circular transfer length method (TLM) patterns. In constrast to Ni contact, Ni/Ti/Al contact shows perfectly linear I-V characteristics, and possesses much lower contact resistance of about $2\sim3\times10^{-4}\Omega{\cdot}cm^2$ even after low-temperature RTA at $840^{\circ}C$, which is about 2 orders of magnitude smaller than that of Ni contact. Therefore, it was shown that RTA temperature for ohmic contact formation can be lowered to at least $840^{\circ}C$ without significant compromise of contact resistance. X-ray diffraction (XRD) analysis indicated the existence of intermetallic compounds of Ni and Al as well as $NiSi_{1-x}$, but characteristic peaks of $Ti_{3}SiC_2$, a probable narrow-gap interfacial alloy responsible for low-resistance Ti/Al ohmic contact formation, were not detected. Therefore, Al in-diffusion into SiC surface region is considered to be the dominant mechanism of improvement in conduction behavior of Ni/Ti/Al contact.

• E2M - 전기 전자와 첨단 소재
• /
• 제8권5호
• /
• pp.619-625
• /
• 1995

Polycrystalline CdTe thin film has been studied for photovoltaic application due to the 1.45 eV band gap energy ideal for solar energy conversion and high absorption coefficient. The formation of low resistance contact to p-CdTe is difficult because of large work function(>5.5eV). Common methods for ohmic contact to p-CdTe are to form a p+ region under the contact by in-diffusion of contact material to reduce the barrier height and modify a p-CdTe surface layer using chemical treatment. In this study, the surface chemical treatment of p CdTe was carried out by H$\_$3/PO$\_$4/+HNO$\_$3/ or K$\_$2/Cr$\_$2/O$\_$7/+H$\_$2/SO$\_$4/ solution to provide a Te-rich surface. And various thin film contact materials such as Cu, Au, and Cu/Au were deposited by E-beam evaporation to form ohmic contact to p-CdTe. After the metallization, post annealing was performed by oven heat treatment at 150.deg. C or by RTA(Rapid Thermal Annealing) at 250-350.deg. C. Surface chemical treatments of p-CdTe thin film improved metal/p-CdTe interface properties and post heat treatment resulted in low contact resistivity to p-CdTe.Of the various contact metal, Cu/Au and Cu show low contact resistance after oven and RTA post-heat treatments, respectively.

• 비파괴검사학회지
• /
• 제33권2호
• /
• pp.187-192
• /
• 2013

크랙 계면에서의 접촉 열저항에 의해 만들어지는 온도 강하 특성을 적외선을 이용하여 측정함으로써 피로균열을 검사하였다. 크랙과 같은 불연속면을 지나는 열 유동은 연속체에서와는 달리 접촉경계면에서 급격한 온도구배를 나타내는데 이 변화를 표면에서의 적외선 방사량으로 측정하여 피로균열의 위치를 탐지하였다. 표준 피로균열 시편의 중앙부에 노치를 생성한 후 저주기 피로균열을 노치 끝단으로부터 발생시킨 다음, 이 시편의 한쪽 끝단에 할로겐램프를 이용하여 일정한 열을 가함으로서 시편의 길이 방향으로 열 유동이 일어나도록 하면서 시편의 표면온도 분포를 적외선 실험장치로 계측하였다. 열 유동이 크랙을 지나면서 온도구배가 크게 변화하는 것을 적외선 열화상 이미지로부터 알 수 있었으며 균열 면에서의 적외선 온도 데이터로부터 크랙의 위치와 크기를 평가할 수 있음을 실험적으로 확인하였다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회B
• /
• pp.2082-2087
• /
• 2008

The heat transfer process from steam to web through the cylinder drum consists of the thermal resistance by condensate thickness. thickness of shell, and the contact resistance between cylinder and web. The most thermal resistance in conventional cylinder drum dryer is generated by condensate, which is increased by the increase on revolution per minute(RPM). Therefore, the increase of RPM for the production enhancement results in the more thermal resistance, and eventually RPM is restricted. In this study, the theoretical analysis on the characteristics of heat transfer in cylinder drum for paper dryer was performed in the stationary state of steam in drum. The overall heat transfer coefficient, steam quantity and heat transfer quantity were predicted by diameter and length of drum, condensate thickness, revolution per minute and steam temperature for experimental apparatus design.

• Safety and Health at Work
• /
• 제11권4호
• /
• pp.405-417
• /
• 2020

Background: Electrical socket outlets are used continuously until a failure occurs because they have no indication of manufacturing date or exchange specifications. For this reason, 659 electrical fires related to electrical socket outlets broke out in the Republic of Korea at 2018 only, an increase year on year. To reduce electrical fires from electrical socket outlets, it is necessary to perform an accelerated test and analyze the thermal, insulation resistance, and material properties of electrical socket outlets by installation years. Methods: Thermal characteristics were investigated by measured the temperature increase of electrical socket outlets classified according to year with variation of the current level. Insulation resistance characteristics was measured according to temperature for an electrical socket outlets by their years of use. Finally, to investigate the thermal and insulation resistance characteristics in relation to outlet aging, this study analyzed electrical socket outlets' conductor surface and content, insulator weight, and thermal deformation temperature. Results: Analysis showed, regarding the thermal characteristics, that electrical socket outlet temperature rose when the current value increased. Moreover, the longer the time that had elapsed since an accelerated test and installation, the higher the electrical socket outlet temperature was. With respect to the insulation resistance properties, the accelerated test (30 years) showed that insulation resistance decreased from 110 ℃. In relation to the installation year (30 years), insulation resistance decreased from 70 ℃, which is as much as 40 ℃ lower than the result found by the accelerated test. Regarding the material properties, the longer the elapsed time since installation, the rougher the surface of conductor contact point was, and cracks increased. Conclusion: The 30-year-old electrical socket outlet exceeded the allowable temperature which is 65 ℃ of the electrical contacts at 10 A, and the insulation resistance began to decrease at 70 ℃. It is necessary to manage electrical socket outlets that have been installed for a long time.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2012년도 추계학술대회 논문집
• /
• pp.723-724
• /
• 2012

• 한국표면공학회지
• /
• 제25권3호
• /
• pp.107-116
• /
• 1992

The optimum thickness of Pd-Ni plated layers used as an electrical contact film was investigated by evaluating mechanical, thermal and environmental characteristics. The variations of morphologies and chemical compositions were studied by using SEM, EDS and ESCA. As a result of wear test, the wear resistance behavior of the gold plated layers was not changed with the sliding velocity changes. The palladium-nickel plated layer showed better wear resistance than the gold plated layer at low sliding velocity, but it showed poor wear resistance at high sliding velocity. Under the thermal condition of $400^{\circ}C$ in air, the gold thickness of $2\mu\textrm{m}$ without underplate on phosphorous bronze formed copper oxide on the surface layer by rapid diffusion of copper whereas the gold thickness of $0.8\mu\textrm{m}$ deposited on nickel and palladium-nickel underplate was stable at $400^{\circ}C$. Under the sulfur dioxide environments, the gold thickness of $0.3\mu\textrm{m}$ deposited on the nickel thickness of$ 3\mu\textrm{m}$ and the palladium-nickel thickness of $2\mu\textrm{m}$ underplate was more corrosion-resistant than the gold thickness of $2\mu\textrm{m}$ without underplate on phosphorous bronze. Under the nitric acid vapor environment, corrosion resistance of the gold film was superior to an equivalent thickness of the palladium-nickel film.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제17권2호
• /
• pp.283-287
• /
• 2017

Recently, Ni-InGaAs has been required for high-performance III-V MOSFETs as a promising self-aligned material for doped source/drain region. As downscaling of device proceeds, reduction of contact resistance ($R_c$) between Ni-InGaAs and n-InGaAs has become a challenge for higher performance of MOSFETs. In this paper, we compared three types of sample, vacuum, 2% $H_2$ and 4% $H_2$ annealing condition in rapid thermal annealing (RTA) step, to verify the reduction of $R_c$ at Ni-InGaAs/n-InGaAs interface. Current-voltage (I-V) characteristic of metal-semiconductor contact indicated the lowest $R_c$ in 4% $H_2$ sample, that is, higher current for 4% $H_2$ sample than other samples. The result of this work could be useful for performance improvement of InGaAs n-MOSFETs.

• Transactions on Electrical and Electronic Materials
• /
• 제18권5호
• /
• pp.253-256
• /
• 2017

A thin Te interlayer was applied to a Ni/n-InGaAs contact to reduce the contact resistance between Ni-InGaAs and n-InGaAs. A 5-nm-thick Te layer was first deposited on a Si-doped n-type $In_{0.53}Ga_{0.47}As$ layer, followed by in situ deposition of a 30-nm-thick Ni film. After the formation of the Ni-InGaAs alloy by rapid thermal annealing at $300^{\circ}C$ for 30 s, the extracted specific contact resistivity (${\rho}_c$) reduced by more than one order of magnitude from $2.86{\times}10^{-4}{\Omega}{\cdot}cm^2$ to $8.98{\times}10^{-6}{\Omega}{\cdot}cm^2$ than that of the reference sample. A thinner Ni-InGaAs alloy layer with a better morphology was obtained by the introduction of the Te layer. The improved interface morphology and the graded Ni-InGaAs layer formed at the interface were believed to be responsible for ${\rho}_c$ reduction.