• 한국재료학회:학술대회논문집
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• 한국재료학회 1996년도 재료학회 춘계학술발표회
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• pp.59-59
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• 1996

• 한국재료학회지
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• 제13권2호
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• pp.88-93
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• 2003

Co/Ti bilayer structure in Co salicide process helps to the improvement of device speed by lowering contact resistance due to the epitaxial growth of $CoSi_2$layers. We investigated the epitaxial growth and interfacial mass transport of $CoSi_2$layers formed from $150 \AA$-Co/Ti structure with two step rapid thermal annealing (RTA). The thicknesses of Ti layers were varied from 20 $\AA$ to 100 $\AA$. After we confirmed the appropriate deposition of Ti film even below $100\AA$-thick, we investigated the cross sectional microstructure, surface roughness, eptiaxial growth, and mass transportation of$ CoSi_2$films formed from various Ti thickness with a cross sectional transmission electron microscopy XTEM), scanning probe microscopy (SPM), X-ray diffractometery (XRD), and Auger electron depth profiling, respectively. We found that all Ti interlayer led to$ CoSi_2$epitaxial growth, while $20 \AA$-thick Ti caused imperfect epitaxy. Ti interlayer also caused Co-Ti-Si compounds on top of $CoSi_2$, which were very hard to remove selectively. Our result implied that we need to employ appropriate Ti thickness to enhance the epitaxial growth as well as to lessen Co-Ti-Si compound formation.

• 한국재료학회지
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• 제8권6호
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• pp.484-492
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• 1998

단결정 Si기판위의 Co/Ti 이중층으로부터 형성된 Co 실리사이드의 에피텍셜 성장기구에 대하여 조사하였다. 실리사이드화 과정중 Ti원자들이 저온상의 CoSi결정구조의 tetrahedral site들을 미리 점유해 있음으로 인하여, $CoSi_{2}$ 결정구조로 바뀌는 과정에서 Si원자들이 나중에 제위치를 차지하기 어렵게 되는 효과 때문이다. 그리고 Ti중간층은 반응의 초기단계에 Co-Ti-O 삼원계 화합물을 형성하는데, 이 화합물은 실리사이드화 과정중 반응 제어층으로 작용하여 에피텍셜 실리사이드 형성에 중요한 역할을 한다. 최종 열처리 층구조 Ti oxide/Co-Ti-Si/epi/$Cosi_{2}$(100) Si 이었다.

• 한국표면공학회지
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• 제35권6호
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• pp.377-382
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• 2002

We investigated the appropriate wet cleaning process for Co-Ti-Si compounds formed on top of cobalt disilicide made from Co/Ti deposition and two rapid thermal annealing (RTA). We employed three wet cleaning processes, WP1 ($H_2$SO$_4$ etchant), WP2 ($NH_4$OH etchant), and WP3 which execute sequentially WP1 and WP2 after the first RTA. All samples were cleaned with BOE etchant after the second RTA. We characterized the sheet resistance with process steps by a four-point probe, the microstructure evolution by a cross detail sectional transmission electron microscope, a Auger depth profiler, and a X-ray diffractometer (XRD). We confirmed WP3 wet cleaning process were the most suitable to remove CoTiSi layer selectively.

• 한국재료학회지
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• 제12권11호
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• pp.865-869
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• 2002

We investigated the reaction stability of titanium, cobalt and their bilayer films with side-wall spacer materials of SiO$_2$ for the salicide process. We prepared Ti 350 $\AA$, Co 150 $\AA$, Co 150 $\AA$/Ti 100 $\AA$ and Ti 100 $\AA$/Co 150 $\AA$ films on 1000 $\AA$-thick thermally grown SiO$_2$ substrates, respectively. Then the samples were rapid thermal annealed at the temperatures of $500^{\circ}C$, $600^{\circ}C$, and $700^{\circ}C$ for 20 seconds. We characterized the sheet resistance of the metallic layers with a four-point probe, surface roughness with scanning probe microscope, residual phases with an Auger depth profilometer, phase identification with a X-ray diffractometer, and cross-sectional microstructure evolution with a transmission electron microscope, respectively. We report that Ti reacted with silicon dioxide spacers above $700^{\circ}C$, Co agglomerated at $600^{\circ}C$, and Co/Ti, Ti/Co formed CoTi compound requiring a special wet process.

• 한국주조공학회지
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• 제15권4호
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• pp.368-376
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• 1995

An Al-composite material was fabricated with using the rheocompocasting process and the microstructure of the Al-Cu/SiCp composite material was investigated depending on the stirring times and the amount of Ti additions. The distribution of SiC dispersion shows the good result at the stirring time of 30 min. The degree of microdistribution of the $Al_2Cu$ and SiCp is improved when the amount of Ti addition is increased. At the compositon of 0.3%Ti, the primary solid is the compound of $Al_3Ti$ and no exist of the SiCp and $Al_2Cu$ phase around the primary $Al_3Ti$. In the process of compositization, SiCp is found at the primary and final solid parts and is found at the final solid part after remelting. $Al_2Cu$ and SiCp are distributed around and outside of dendrite or independently after remelting, which is different from the process of compositization.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.215-216
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• 2013

The silicide is a compound of Si with an electropositive component. Silicides are commonly used in silicon-based microelectronics to reduce resistivity of gate and local interconnect metallization. The popular silicide candidates, CoSi2 and TiSi2, have some limitations. TiSi2 showed line width dependent sheet resistance and has difficulty in transformation of the C49 phase to the low resistive C54. CoSi2 consumes more Si than TiSi2. Nickel silicide is a promising material to substitute for those silicide materials providing several advantages; low resistivity, lower Si consumption and lower formation temperature. Nickel silicide (NiSi) nanowire (NW) has features of a geometrically tiny size in terms of diameter and significantly long directional length, with an excellent electrical conductivity. According to these advantages, NiSi NWs have been applied to various nanoscale applications, such as interconnects [1,2], field emitters [3], and functional microscopy tips [4]. Beside its tiny geometric feature, NW can provide a large surface area at a fixed volume. This makes the material viable for photovoltaic architecture, allowing it to be used to enhance the light-active region [5]. Additionally, a recent report has suggested that an effective antireflection coating-layer can be made with by NiSi NW arrays [6]. A unique growth mechanism of nickel silicide (NiSi) nanowires (NWs) was thermodynamically investigated. The reaction between Ni and Si primarily determines NiSi phases according to the deposition condition. Optimum growth conditions were found at $375^{\circ}C$ leading long and high-density NiSi NWs. The ignition of NiSi NWs is determined by the grain size due to the nucleation limited silicide reaction. A successive Ni diffusion through a silicide layer was traced from a NW grown sample. Otherwise Ni-rich or Si-rich phase induces a film type growth. This work demonstrates specific existence of NiSi NW growth [7].

• 대한치과보철학회지
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• 제45권2호
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• pp.169-181
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• 2007

Statement of problem: Titanium is well known as a proper metal for the dental restorations, because it has an excellent biocompatibility, resistance to corrosion, and mechanical property. However, adhesion between titanium and dental porcelains is related to the diffusion of oxygen to the reaction layers formed on cast-titanium surfaces during porcelain firing and those oxidized layers make the adhesion difficult to be formed. Many studies using mechanical, chemical and physical methods to enhance the titanium-ceramic adhesion have been actively performed. Purpose: This study meant to comparatively analyse the adhesion characteristics depending on different titanium surface coatings after coating the casts and wrought titanium surfaces with Au and TiN. Material and method: In this study, the titanium specimens (CP-Ti, Grade 2, Kobe still Co. Japan) were categorized into cast and wrought titanium. The wrought titanium was cast by using the MgO-based investment(Selevest CB, Selec). The cast and wrought titanium were treated with Au coating($ParaOne^{(R)}$., Gold Ion Sputter, Model PS-1200) and TiN coating(ATEC system, Korea) and the ultra low fusing dental porcelain was fused and fired onto the samples. Biaxial flection test was done on the fired samples and the porcelain was separated. The adhesion characteristics of porcelain and titanium after firing and the specimen surfaces before and after the porcelain fracture test were observed with SEM. The atomic percent of Si on all sample surfaces was comparatively analysed by EDS. In addition, the constituents of specimen surface layers after the porcelain fracture and the formed compound were evaluated by X-ray diffraction diagnosis. Result: The results of this study were obtained as follows : 1. The surface characteristics of cast and wrought titanium after surface treatment(Au, TiN, $Al_2O_3$ sandblasting) were similar and each cast and wrought titanium showed similar bonding characteristics. 2. Before and after the biaxial flection test, the highest atomic weight change of Si component was found in $Al_2O_3$ sandblasted wrought titanium(28.6at.% $\rightarrow$ 8.3at.%). On the other hand, the least change was seen in Au-Pd-In alloy(24.5at.% $\rightarrow$ 9.1at.%). 3. Much amount of Si components was uniformly distributed in Au and TiN coated titanium, but less amount of Si's was unevenly dispersed on Al2O3 sandblasting surfaces. 4. In X-ray diffraction diagnosis after porcelain debonding, we could see $Au_2Ti$ compound and TiN coating layers on Au and TiN coated surfaces and $TiO_2$, typical oxide of titanium, on all titanium surfaces. 5. Debonding of porcelain on cast and wrought titanium surface after the biaxial flection is considered as a result of adhesion deterioration between coating layers and titanium surfaces. We found that there are both adhesive failure and cohesive failure at the same time. Conclusion: These results showed that the titanium-ceramic adhesion could be improved by coating cast and wrought titanium surfaces with Au and TiN when making porcelain fused to metal crowns. In order to use porcelain fused to titanium clinically, it is considered that coating technique to enhance the bonding strength between coating kKlayers and titanium surfaces should be developed first.