• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.7
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• pp.486-493
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• 2003

Schottky type A $l_{0.33}$G $a_{0.67}$N ultraviolet photodetectors were fabricated on the MOCVD grown AlGaN/ $n^{＋}$-GaN and AlGaN/AlGaN interlayer/ $n^{＋}$-GaN structures. The grown layers have the carrier concentrations of -$10^{18}$, and the mobilities were 236 and 269 $\textrm{cm}^2$/V.s, respectively. After mesa etching by ICP etching system, the Si3N4 layer was deposited for passivation between the contacts and Ti/AL/Ni/Au and Pt were deposited for ohmic and Schottky contact, respectively. The fabricated Pt/A $l_{0.33}$G $a_{0.67}$N Schottky diode revealed a leakage current of 1 nA for samples with interlayer and 0.1$\mu\textrm{A}$ for samples without interlayer at a reverse bias of -5 V. In optical measurement, the Pt/A $l_{0.33}$G $a_{0.67}$N diode with interlayer showed a cut-off wavelength of 300 nm, a prominent responsivity of 0.15 A/W at 280 nm and a UV-visible extinction ratio of 1.5x$10^4./TEX>.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.2
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• pp.277-282
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• 2017

Nickel germanide (NiGe) is one of the most promising alloy materials for source/drain (S/D) of Ge MOSFETs. However, NiGe has limited thermal stability up to $450^{\circ}C$ which is a challenge for fabrication of Ge MOSFETs. In this paper, a novel method is proposed to improve the thermal stability of NiGe using Co interlayer. As a result, we found that the thermal stability of NiGe was improved from $450^{\circ}C$ to $570^{\circ}C$ by using the proposed Co interlayer. Furthermore, we found that current-voltage (I-V) characteristic was improved a little by using Co/Ni/TiN structure after post-annealing. Therefore, NiGe formed by the proposed Co interlayer that is, Co/Ni/TiN structure, is a promising technology for S/D contact of Ge MOSFETs.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.135.2-135.2
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• 2005

• Journal of the Korean Ceramic Society
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• v.36 no.8
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• pp.835-842
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• 1999

Si3N4 -Si3N4 joints were made using Ag-Cu-Ti and Ag-Cu-In-Ti via brazing method and the change in joint strength was investigated after heat treatment at $400^{\circ}C$ or $650^{\circ}C$ for up to 2000h. The initial strength of as-brazed joints with Ag-Cu-In-Ti was lower but the reduction of the strength was less dramatic than that with Ag-Cu-Ti. The joints made of a new brazing alloy Au-Ni-Cr-Mo-Fe which is developed for high temperature applications were heat-treated at $650^{\circ}C$ for 1000h. As the heat treatment time increased the bond strength increased. The results of the joining system with Mo or Cu interlayer showed that the strength of the joint with Mo interlayer was higher but the system incurred problems in joint production Also it was found from oxidation experiment that Ti and In affected the oxidation resistance of brazing alloy.

• Journal of Surface Science and Engineering
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• v.39 no.5
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• pp.199-205
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• 2006

Titanium nitride (TiN) coatings were produced on AISI 420 stainless steel by DC magnetron sputtering of a Ti target changing the processing variables, such as the flow rate of $N_2/Ar$, substrate temperature and the existence of Ti interlayer between TiN coatings and substrates. The hardness and residual stress in the films were investigated using nanoindentation and a laser scanning device, respectively. The stoichiometry and surface morphology were investigated using X-Ray Diffraction and SEM. The corrosion property of the films was also studied using a polarization method in NaCl (0.9%) solution. Mechanical properties including hardness and residual stress were related to the ratio of $N_2/Ar$ flow rate. The corrosion resistance also was related to the processing variables.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.11
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• pp.1149-1155
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• 2004

In this paper, novel methods for improvement of thermal stability of Ni-germano Silicide were proposed for nano CMOS applications. It was shown that there happened agglomeration and abnormal oxidation in case of Ni-germano Silicide using Ni only structure. Therefore, 4 kinds of tri-layer structure, such as, Ti/Ni/TiN, Ni/Ti/TiN, Co/Ni/TiN and Ni/Co/TiN were proposed utilizing Co and Ti interlayer to improve thermal stability of Ni-germano Silicide. Ti/Ni/TiN structure showed the best improvement of thermal stability and suppression of abnormal oxidation although all kinds of structures showed improvement of sheet resistance. That is, Ti/Ni/TiN structure showed only 11 ohm/sq. in spite of 600 $^{\circ}C$, 30 min post silicidation annealing while Ni-only structure show 42 ohm/sq. Therefore, Ti/Ni/TiN structure is highly promising for nano-scale CMOS technology.

• Journal of Surface Science and Engineering
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• v.52 no.2
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• pp.53-57
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• 2019

Stability and activity of boron doped diamond (BDD) electrode are key factors for water treatment. In this study, BDD electrodes were prepared on various substrates such as Nb, Si, Ti, and $TiN_x/Ti$ by hot filament chemical vapor deposition (HFCVD) method. BDD/Ti film showed the delamination between BDD and Ti substrate due to the formation of TiC layer caused by diffusion of carbon. On the other hand, $BDD/TiN_x/Ti$ showed remarkably improved stability, compared to BDD/Ti. It was confirmed that $TiN_x$ intermediate layer act as barrier layer for diffusion of carbon. High potential window of 2.8 eV was maintained on the $BDD/TiN_x/Ti$ electrode and, better wastewater treatment capability and longer electrode working life than BDD/Nb, BDD/Si and BDD/Ti were obtained.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.215-218
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• 2005

Co-interlayer와 $SiO_2$ 상부막이 nickel germanosilicide 박막의 열안정성에 미치는 영향을 연구하였다. Nickel germanosilicide는 SiGe 기판 위에 Ni(8nm)/TiN(25nm), Ni(6m)/Co(2nm)/TiN(25nm)을 증착하여 각각 one step RIP($500^{\circ}C$)와 two step RTP(500. $700^{\circ}C$)로 형성되었다. 50과 10nm 두께의 $SiO_2$ 박막을 실리사이드 위에 증착하고, 550, 600, $650^{\circ}C$에서 30분간 열처리한 후 면저항 값을 측정하여 열안정성을 평가하였다.

• Journal of Mechanical Science and Technology
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• v.16 no.9
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• pp.1078-1083
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• 2002

Ceramics are significantly used in many industrial applications due to their excellent mechanical and thermal properties such as high temperature strength, low density, high hardness, low thermal expansion, and good corrosion resistive properties, while their disadvantages are brittleness, poor formability and high manufacturing cost. To combine advantages of ceramics with those of metals, they are often used together as one composite component, which necessiates reliable joining methods between metal and ceramic. Direct brazing using an active filler metal has been found to be a reliable and simple technique, producing strong and reliable joints. In this study, the fracture characteristics of Si$_3$N$_4$ ceramic joined to ANSI 304L stainless steel with a Ti-Ag-Cu filler and a Cu (0.25-0.3 mm) interlayer are investigated as a function of strain rate and temperature. In order to evaluate a local strain a couple of strain gages are pasted at the ceramic and metal sides near joint interface. As a result the 4-point bending strength and the deflection of interlayer increased at room temperature with increasing strain rate. However bending strength decreased with temperature while deflection of interlayer was almost same. The fracture shapes were classified into three groups ; cracks grow into the metal-brazing filler line, the ceramic-brazing filler line or the ceramic inside.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.5
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• pp.390-396
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• 2003

As the design rule of device continued to shrink, the contact resistance in small contact size became important. Although the conventional TiN/Ti structure as a ohmic layer has been widely used, we propose a new TiN/Co film structure. We characterized a contact resistance by using a chain pattern and a KELVIN pattern, and a leakage current determined by current-voltage measurements. Moreover, the microstructure of TiN/ Ti/ silicide/n$\^$+/ contact was investigated by a cross-sectional transmission electron microscope (TEM). The contact resistance by the Co ohmic layer showed the decrease of 26 % compared to that of a Ti ohmic layer in the chain resistance, and 50 ％ in KELYIN resistance, respectively. A Co ohmic layer shows enough ohmic behaviors comparable to the Ti ohmic layer, while higher leakage currents in wide area pattern than Ti ohmic layer. We confirmed that an uniform silicide thickness and a good interface roughness were able to be achieved in a CoSi$_2$ Process formed on a n$\^$+/ silicon junction from TEM images.