• 한국전기전자재료학회논문지
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• 제31권3호
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• pp.141-145
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• 2018

Ni-InGaAs shows promise as a self-aligned S/D (source/drain) alloy for n-InGaAs MOSFETs (metal-oxide-semiconductor field-effect transistors). However, limited thermal stability and instability of the microstructural morphology of Ni-InGaAs could limit the device performance. The in situ deposition of a Pd interlayer beneath the Ni layer was proposed as a strategy to improve the thermal stability of Ni-InGaAs. The Ni-InGaAs alloy layer prepared with the Pd interlayer showed better surface roughness and thermal stability after furnace annealing at $570^{\circ}C$ for 30 min, while the Ni-InGaAs without the Pd interlayer showed degradation above $500^{\circ}C$. The Pd/Ni/TiN structure offers a promising route to thermally immune Ni-InGaAs with applications in future n-InGaAs MOSFET technologies.

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

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.310-313
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• 2000

In this study, the Au/Ni and Au/Ni/Si/Ni layers prepared by electron beam evaporation were used to form ohmic contacts on p-type GaN. Before rapid thermal annealing, the current-voltage(I-V) characteristic of Au/Ni and Au/Ni/Si/Ni contact on p-type GaN film shows non-ohmic behavior. A Specific contact resistance as 3.4$\times$10$^{-4}$ Ω-$\textrm{cm}^2$ was obtained after 45$0^{\circ}C$-RTA. The Schottky barrier height reduction may be attributed to the presence of Ga-Ni and Ga-Au compounds, such as Ga$_4$Ni$_3$, Ga$_4$Ni$_3$, and GaAu$_2$ at the metal - semiconductor interface. The mixing behaviors of both Ni and Au have been studied by using X-ray photoelectron spectroscopy. In addition, X-ray diffraction measurements indicate that the Ni$_3$N, NiGa$_4$, Ni$_2$Si, and Ni$_3$Si$_2$ Compounds were formed at the metal-semiconductor interface.

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

• 세라미스트
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• 제10권3호
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• pp.28-33
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• 2007

The structural and optical properties of Ni-doped transparent glass-ceramics are reviewed. The quantum efficiencies of ceramics were examined to explore suitable crystalline phase for Ni-doping in glass-ceramics. Inverse spinel $LiGa_5O_8$ have the quantum efficiency of almost 100 % at room temperature. Transparent glass ceramics containing $LiGa_5O_8$ was successfully synthesized by heat treatment of $Li_2O-Ga_2-O_3-SiO_2-NiO$ glass. Most of $Ni^{2+}$ ions in glass-ceramic were incorporated into $LiGa_5O_8$ nanocrystals. The near-infrared emission covering from the O-band to L-band (1260-1625 nm) was observed from the Ni-doped $Li_2O-Ga_2O_3-SiO_2$ glass-ceramic though it was not observed from the as-cast glass. The lifetime of the emission was about $580\;{\mu}sec$ even at 300K. The emission quantum efficiency was evaluated as about 10 % that is enough high for practical usage as gain media of optical fiber amplifiers. The figure of merit (the product of the stimulated emission cross section and lifetime) was as high as that of rare-earth-doped glasses. The broad bandwidth, high quantum efficiency and high figure of merit show that transparent glass-ceramics containing $Ni^{2+}:LiGa_5O_8$ nanocrystals are promising candidates as novel ultra-broadband gain media.

• 한국진공학회지
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• 제12권S1호
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• pp.104-106
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• 2003

In this study, the electronic structures and physical properties of Ni$_2$MnGa alloy films and their dependence on the order-disorder structural transitions were investigated. The results show that the ordered films behave nearly the same as the bulk $Ni_2$MnGa alloy, including the martensitic transformation at 200 K. Unexpectedly, the disordering in $Ni_2$MnGa alloy films does not lead to any appreciable magnetic ordering down to 4 K. An annealing of the disordered films restores the ordered structure with an almost full recovery of the magnetic and the transport properties of the ordered $Ni_2$MnGa alloy films. A possible explanation of the disappearance of magnetic moment in the disordered film is given by using the ab initio first-principles electronic-structure calculations.

• 전기전자학회논문지
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• 제25권3호
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• pp.511-516
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• 2021

AlGaN/GaN 반도체 위에 금속이 접합된 HEMT와 SiO₂와 NiO를 게이트 층간막으로 갖는 MOSHFET를 제작하고 NiO 박막에 따른 효과와 특성변화의 원인을 연구하였다. HEMT 구조에서 보인 -3.79 V의 문턱전압은 SiO₂를 층간막으로 했을 때 - 5.52 V로 -1.73 V의 음방향 변화를, NiO를 층간막으로 했을 때 -2.76 V로 +1.03 V의 양방향 변화를 나타냈다. 또 NiO MOSFET의 경우 선형성이 증가하여 넓은 범위에 걸쳐 균일한 트랜스컨덕턴스 특성을 나타냈으며 0 V 이상의 게이트 전압에서는 HEMT와 SiO₂ MOSHFET보다 더 높은 값을 보였다. 게이트에 입력된 펄스신호가 -5 V~0 V로 스윙할 때 HEMT의 포화 드레인 전류는 0.1 Hz~10 Hz의 주파수에서 20%의 감소를 보인 뒤 그 값을 유지하였으나, NiO MOSHFET은 10 Hz에서부터 지속적으로 감소하여 서로 다른 응답특성을 보였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1998년도 추계학술발표강연 및 논문개요집
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• pp.151-151
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• 1998

• 열처리공학회지
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• 제22권6호
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• pp.354-360
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• 2009

This paper reports the oxidation mechanism of epitaxial Ni thin films grown on GaN/sapphire(0001) substrates, investigated by real-time x-ray diffraction and scanning electron microscopy. At the initial stage of oxidation process, a thin NiO layer with a thickness of ${\sim}50\;{\AA}$ was formed on top of the Ni films. The growth of such NiO layer was saturated and then served as a passive oxide layer for the further oxidation process. For the second oxidation stage, host Ni atoms diffused out to the surfaces of initially formed NiO layer through the defects running vertically to form NiO grains, while the sites that were occupied by host Ni, became voids. The crystallographic properties of resultant NiO films, such as grain size and mosaic distribution, rely highly on the oxidation temperatures.

• 마이크로전자및패키징학회지
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• 제28권4호
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• pp.25-29
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• 2021

본 연구에서는 HVPE 방법을 사용하여 Ni-Pd and Carbon-Nanotube nanoalloys (Ni-Pd-CNT) 위에 α-Ga₂O₃을 성장시켜 Ni-Pd-CNT에 따른 효과를 확인하였다. 그 결과, 무전해 Ni 도금 시간 40초에서 성장한 α-Ga₂O₃ 에피층의 두께는 11 ㎛로 확인되었다. 또한, α-Ga₂O₃ 에피층의 표면 형태는 균열 발생 없이 기판에 대한 우수한 접착력을 보여주었다. 결과적으로, 성장과정에서 발생한 수평 성장에 의해 α-Ga₂O₃ 대의 비대칭면인 ($10{\bar{1}}4$) FWMH 값을 크게 감소할 수 있었다.