• Korean Journal of Materials Research
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• v.10 no.1
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• pp.21-28
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• 2000

Refractory metals, W and Ti, and their nitrides, $W_2N$ and TiN, were investigated for using as an ohmic contact material with SiC single crystalline thin films. The possibility of nitride materials for using as a stable ohmic contact material of SiC at high temperatures was examined by considering the thermal stability depending on the heat treatment temperature, their electrical properties and protective behavior from the interdiffusion. W contact with SiC thin films, deposited by using new organosilicon precursor, bis-trimethylsilylmethane, showed the lowest resistivity, $2.17{\times}10^{-5}$Ω$\textrm{cm}^2$. On the other hand, Ti-based contact materials showed higher contact resistivity than W-based ones. The oxidation of contact materials was restricted by applying Pt thin films on those electrodes. Nitride electrodes had rather stable electrical properties and better protective behavior from interdiffusion than metal electrodes.

• Korean Journal of Materials Research
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• v.7 no.10
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• pp.884-890
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• 1997

Sputtering 방법을 통해 Si기판 위에 Ti와 TiN박막을 증착하고 저압 반응관내에서 Cu*hfac)(TMVS)를 precursor로 사용 MOCVD Cu박막을 증착하여 Cu/TiN/Ti/Si구조의 다층박막을 제조하였고 이에 대한 열처리 방식 및 분위기 변화 등을 통해 열처리 조건에 따른 Cu 박막의 특성 변화에 대해 조사하였다. 열처리 방식으로는 Cu박막을 형성한 후 공기 중에 노출이 없이 바로 열처리하여 Cu산화물 형성을 억제할 수 있는 in-situ열처리 방식이 유리하고, 열처리 분위기로는 Cu 박막의 표면이나 결정립계 내에 존재하는 Cu 산화물을 환원시켜 줄 수 있는 H$_{2}$(10%)/Ar분위기가 표면평탄화, 결정립 크기 증가 및 비저항 감소측면에서 우수한 특성의 Cu박막을 얻을 수 있음을 확인하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.619-619
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• 2013

The interfacial state between $Ta_2O_5$ and a Si substrate during the growth of $Ta_2O_5$ films by atomic layer deposition (ALD) was investigated using in-situ synchrotron radiation photoemission spectroscopy (SRPES). A newly synthesized liquid precursor Ta($N^tBu$) $(dmamp)_2Me$ was used as the metal precursor, with Ar as a purging gas and $H_2O$ as the oxidant source. After each half reaction cycle, samples were analyzed using in-situ SRPES under ultrahigh vacuum at room temperature. SRPES analysis revealed that Ta suboxide and Si dioxide were formed at the initial stages of $Ta_2O_5$ growth. However, the Ta suboxide states almostdisappeared as the ALD cycles progressed. Consequently, the $Ta^{5+}$ state, which corresponds with the stoichiometric $Ta_2O_5$, only appeared after 4.0 cycles. Additionally, tantalum silicate was not detected at the interfacial states between $Ta_2O_5$ and Si. The measured valence band offset between $Ta_2O_5$ and the Si substrate was 3.22 eV after 3.0 cycles.

• Bulletin of the Korean Chemical Society
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• v.25 no.11
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• pp.1661-1666
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• 2004

The reaction of titanium tetraisopropoxide with 2 equiv of N,N-diethyl acetoacetamide affords Ti($O^iPr)_2(CH_3COCHCONEt_2)_2$ (1) as colorless crystals in 80% yield. Compound 1 is characterized by spectroscopic (Mass and $^1H/^{13}C$ NMR) and microanalytical data. Molecular structure of 1 has been determined by a single crystal X-ray diffraction study, which reveals that it is a monomeric, cis-diisopropoxide and contains a six coordinate Ti(IV) atom with a cis($CONEt_2$), trans($COCH_3$) configuration (1a) in a distorted octahedral environment. Variable-temperature $^1H$ NMR spectra of 1 indicate that it exists as an equilibrium mixture of cis, trans (1a) and cis, cis (1b) isomers in a 0.57 : 0.43 ratio at -20$^{\circ}C$ in toluene-$d_8$ solution. Thermal properties of 1 as a MOCVD precursor for titanium dioxide films have been evaluated by thermal gravimetric analysis and vapor pressure measurement. Thin films of pure anatase titanium dioxide (after annealing above 500$^{\circ}C$ under oxygen) have been grown on Si(100) with precursor 1 in the substrate temperature range of 350- 500$^{\circ}$ using a bubbler-based MOCVD method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.216-216
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• 2009

This paper describes a novel processing technique for the fabrication of polymer-derived SiCN (silicone carbonitride) microstructures for extreme microelectromechanical system (MEMS) applications. A polydimethylsiloxane (PDMS) mold was formed on an SU-8 pattern using a standard UV photolithographic process. Next, the liquid precursor, polysilazane, was injected into the PDMS mold to fabricate free-standing SiCN microstructures. Finally, the solid polymer SiCN microstructure was cross-linked using hot isostatic pressure at $400^{\circ}C$ and 205 bar. The optimal pyrolysis and annealing conditions to form a ceramic microstructure capable of withstanding temperatures over $1400^{\circ}C$ were determined. Using the optimal process conditions, the fabricated SiCN ceramic microstructure possessed excellent characteristics includingshear strength (15.2 N), insulation resistance ($2.163{\times}10^{14}\;{\Omega}$, and BDV (1.2 kV, minimum). Since the fabricated ceramic SiCN microstructure has improved electrical and physical characteristics compared to bulk Si wafers, it may be applied to harsh environments and high-power MEMS applications such as heat exchangers and combustion chambers.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.318-326
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• 1996

This study is to investigate a chemical vapor deposition technique of copper film which is expected to be more useful as metallizations of microcircuit fabrication. An experimental equipment was designed and set-up for this study, and a Cu-precursor used that is a metal-organic compound, named (hfac)Cu(I)VTMS ; (hevaflouoroacetylacetonate trimethyvinylsilane copper). Base pressure of the experimental system is in $10^{-6}$ Torr, and the chamber pressure and the substrate temperature can be controlled in the system. Before the deposition of copper thin film, tungsten or titanium nitride film was deposited onto the silicon wafer. Helium has been used as carrier gas to control the deposition rate. As a result, deposition rate was measured as $1,800\;{\AA}/min$ at $220^{\circ}C$ which is higher than the results of previous studies, and the average surface roughness was measured as about $200\;{\AA}$. A deposition selectivity was observed between W or TiN and $SiO_{2}$ substrates below $250^{\circ}C$, and optimum results are observed at $180^{\circ}C$ of substrate temperature and 0.8 Torr of chamber pressure.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.167.2-167.2
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• 2014

In this work, ZnO shell on mesoporous $SiO_2$ ($ZnO/SiO_2$) was prepared by atomic layer deposition (ALD). Diethylzinc (DEZ) and $H_2O$ were used as precursor of ZnO shell. $ZnO/SiO_2$ sample was characterized by X-ray diffraction (XRD), N2 sorption isotherms, X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FT-IR). $ZnO/SiO_2$ showed higher adsorption capacity of MB than that of bare mesoporous $SiO_2$ and the adsorption capacities of $ZnO/SiO_2$ could be regenerated by UV exposure through the photocatalytic degradation of the adsorbed MB. This system could be used for removing organic dye from water by adsorption and reused after saturation of adsorption due to its photocatalytic regeneration.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.14-17
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• 2006

This paper describes a novel processing technique for fabrication of polymer-derived SiCN (silicone carbonitride) microstructures for super-temperature MEMS applications. PDMS (polydimethylsiloxane) mold is fabricated on SU-8 photoresist using standard UV photolithographic process. Liquid precursor is injected into the PDMS mold. Finally, solid polymer structure is cross-linked using HIP (hot isostatic pressure) at $400^{\circ}C$, 205 bar Optimum pyrolysis and anneal ins conditions are determined to form a ceramic microstructure capable of withstanding over $1400^{\circ}C$. The fabricated SiCN ceramic microstructure has excel lent characteristics, such as shear strength (15.2 N), insulation resistance ($2.163{\times}10^{14}\;{\Omega}$) and BDV (min. 1.2 kV) under optimum process condition.

• Journal of the Korean Ceramic Society
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• v.35 no.8
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• pp.827-835
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• 1998

Blanket Copper films were chemically vapor deposited on six kinds for substrates for scrutinizing the change of characteristics induced by the difference of substrates and seeding layers. Both TiN/Si and {{{{ { SiO}_{2 } }}/Si wafers were used as-recevied and with the Cu-seeding layers of 40${\AA}$ and 160${\AA}$ which were produced by sputtering The CVD processes were exectued at the deposition temperatures between 130$^{\circ}C$ and 260$^{\circ}C$ us-ing (hfc)Cu(VTMS) as a precursor. The deposition rate of 40$^{\circ}C$ Cu-seeded substrates was higher than that of other substrates and especially in seeded {{{{ { SiO}_{2 } }}/Si substrate because of the incubation period reducing in-duced by seeding layer at the same deposition time and temperature. The resistivity of 160${\AA}$ Cu seeded substrate was lower then that of 40 ${\AA}$ because the nucleation and growth behavior in Cu-island is different from the behavior in {{{{ { SiO}_{2 } }} substrate due to the dielectricity of {{{{ { SiO}_{2 } }}.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.309-317
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• 1996

Al2O3 thin films were deposited on Si-wafer (100) using organo-aluminum compounds at low pressure by chemical vapor deposition (CVD) method. The vapor of the organo-metallic precursor was carried by pure N2 gas. The deposition rate increased and then saturated as Tsub increased with increasing the AIP flow rate. The main contamination didn't found in deposited films except carbon. The H-O(H2O) IR absorption band decreased in intensity as the deposition temperature increased, and completely disappeared through annealing.