• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.3
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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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• v.18 no.5
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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.

• Proceedings of the IEEK Conference
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• 2000.06b
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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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• v.17 no.2
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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.

• Ceramist
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• v.10 no.3
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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.

• Journal of the Korean Vacuum Society
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• v.12 no.S1
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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.

• Journal of IKEEE
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• v.25 no.3
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• pp.511-516
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• 2021

The electrical characteristics of AlGaN/GaN/HEMT and MOSHFETs with NiO were studied. The threshold voltage of NiO MOSHFET revealed positive shift of +1.03 V than the -3.79 V of HEMT and negative shift of -1.73 V for SiO₂ MOSHFET. Also, NiO MOSHFET showed better linearity in drain current corresponding to gate voltage and higher transconductance at positive gate voltage than the others. The response of gate pulse with base voltage of -5 V was different for both transistors as HEMT showed 20 % drain current decrease at the frequency range of 0.1 Hz~10 Hz and NiO MOSHFET decreased continuously above 10 Hz.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.11a
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• pp.151-151
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• 1998

• Journal of the Korean Society for Heat Treatment
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• v.22 no.6
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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.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.25-29
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• 2021

This paper demonstrates the utility of the Ni-Pd and carbon-nanotube (Ni-Pd-CNT)-based nanoalloy to improve the α-Ga₂O₃ crystal quality using the halide-vapor-phase epitaxy (HVPE) method. As result, the overall thickness of the α-Ga₂O₃ epitaxial layer increased from a Ni electroless plating time of 40 s to 11 ㎛ after growth. In addition, the surface morphologies of the α-Ga₂O₃ epilayers remained flat and crack-free. The full-width half-maximum results of the X-ray diffraction analysis revealed that the ($10{\bar{1}}4$) diffraction patterns decreased with increasing nominal thickness.