• 한국초전도학회:학술대회논문집
• /
• v.12
• /
• pp.81-81
• /
• 2002

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.76.2-76.2
• /
• 2013

Advanced electronic application areas have strongly required new materials due to the continuous shrinking dimensions of their devices. Specially, the development and use of metal precursors for atomic layer deposition has been extensively focused on application to electronic devices. Thus the systematic design and synthesis of metal compounds with relevant chemical and physical properties, such as stability, volatility, and resistance to air and moisture are very important in the vacuum deposition fields. In many case, organic ligands for metal precursors are especially focused in the related research areas because the large scale synthesis of the metal complexes with excellent properties exclusively depends on the potential usefulness of the ligands. It is recommended for metal complexes to be in monomeric forms because mononuclear complexes generally show high vapor pressures comparing with their oligomeric structure such as dimer and trimer. Simple metal alkoxides complexes are involatile except several examples such as Ti(OiPr)4, Si(OEt)4, and Hf(OtBu)4. Thus the coordinated atom of alkoxide ligands should be crowded in its own environment with some substituents by prohibiting the coordinated atoms from bonding to another metal through oxygen-bridging configuration. Alkoxide ligands containing donor-functionalized group such as amino and alkoxy which can induce the increasing of the coordinative saturation of the metal complexes and the decreasing of the intermolecular interaction between or among the metal compounds. In this presentation, we will discuss the development of metal compounds which adopted donor-functionalized alkoxide ligands derived from their alcohols for electronic application. Some recent results on ALD using metal precursors such as tin, nickel, ruthenium, and tungsten developed in our group will be disclosed.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.659-659
• /
• 2013

Recently, graphene has been intensively studied due to the fascinating physical, chemical and electrical properties. It shows high carrier mobility, high current density, and high thermal conductivity compare with conventional semiconductor materials even it has single atomic thickness. Especially, since graphene has fantastic electrical properties many researchers are believed that graphene will be replacing Si based technology. In order to realize it, we need to prepare the large and uniform graphene. Chemical vapor deposition (CVD) method is the most promising technique for synthesizing large and uniform graphene. Unfortunately, CVD method requires transfer process from metal catalyst. In transfer process, supporting polymer film (Such as poly (methyl methacrylate)) is widely used for protecting graphene. After transfer process, polymer layer is removed by organic solvents. However, it is impossible to remove it completely. These organic residues on graphene surface induce quality degradation of graphene since it disturbs movement of electrons. Thus, in order to get an intrinsic property of graphene completely remove of the organic residues is the most important. Here, we introduce modified wet graphene transfer method without PMMA. First of all, we grow the graphene from Cu foil using CVD method. And then, we deposited several metal films on graphene for transfer layer instead of PMMA. Finally, we fabricate graphene FET devices. Our approaches show low defect density and non-organic residues in comparison with PMMA coated graphene through Raman spectroscopy, SEM and AFM. In addition, clean graphene FET shows intrinsic electrical characteristic and high carrier mobility.

• Journal of the Korean Ceramic Society
• /
• v.28 no.8
• /
• pp.585-592
• /
• 1991

ZnO films were deposited onto Corning glass 7059 substrate in the temperature range from $200^{\circ}C$ to $450^{\circ}C$ by chemical vapor deposition technique using the hydrolysis of Diet ylzinc (DEZ). As the deposition temperature increased from $200^{\circ}C$ to $350^{\circ}C$, the deposition rate increased with the apparent activation energy of ∼23kJ/mole. Further increase of the deposition temperature above $400^{\circ}C$, however, resulted in a reduction of the rate. It was found that ZnO film grew with a strong C-axis preferred orientation at the temperature of $400^{\circ}C$. As the deposition temperature increased, the film resistivity decreased down to ∼0.2 $\Omega$cm at $450^{\circ}C$. The electrical resistivity was governed more likely by electron concentration rather than by electron mobility. Average optical transmission of the films in the optical wavelength range of 400 nm to 900 nm was over 90% and the optical energy band gap of 3.28∼3.32 eV was obtained from the direct transition.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.7
• /
• pp.1573-1578
• /
• 2009

A computational study of the reactions between Zn-containing species, the products of the thermal decomposition of diethylzinc (DEZn) and water was investigated. The Zn-containing species – $C_2H_5)_2,\;HZnC_2H_5,\;and\;(ZnC_2H_5)_2$ – were assumed to react with water during ZnO metal organic chemical vapor deposition (MOCVD). Density functional theory (DFT) calculations at the level of B3LYP/6-311G(d) were employed for the geometry optimization and thermodynamic property evaluation. As a result dihydroxozinc, $Zn(OH)_2$, was the most probable reaction product common for all three Zn-containing species. A further clustering of $Zn(OH)_2$ was investigated to understand the initial stage of ZnO film deposition. In experiments, the reactions of DEZn and water were examined by in-situ Raman scattering in a specially designed MOCVD reactor. Although direct evidence of $Zn(OH)_2$ was not observed, some relevant reaction intermediates were successfully detected to support the validity of the gas phase reaction pathways proposed in the computational study.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.488.2-488.2
• /
• 2014

Carbon-based materials such as carbon nanotubes and graphene have emerged as promising building blocks in applications for nanoelectronics and energy devices due to electrical property, ease of processability, and relatively inert electrochemistry. In recent years, there has been considerable interest in core-shell nanomaterials, in which inorganic nanowires are surrounded by inorganic or organic layers. Especially, carbon encapsulated semiconductor nanowires have been actively investigated by researchers in lithium ion batteries. We report a method to synthesize silicon nanowire (SiNW) core/carbon shell structures by chemical vapor deposition (CVD), using methane (CH4) as a precursor at growth temperature of $1000{\sim}1100^{\circ}C$. Unlike carbon-based materials synthesized via conventional routes, this method is of advantage of metal-catalyst free growth. We characterized these materials with FE-SEM, FE-TEM, and Raman spectroscopy. This would allow us to use these materials for applications ranging from optoelectronics to energy devices such as solar cells and lithium ion batteries.

• Electronics and Telecommunications Trends
• /
• v.3 no.2
• /
• pp.56-60
• /
• 1988

반도체 가스의 순도에 따라 반도체 박막의 특성이 좌우되기 때문에 현재의 고순도 가스에서 초고순도 가스로 사용하여야 한다. 최근 반도체 공정기술은 화학증착법으로 많은 특수 가스를 사용하는데 이런 가스들은 사전에 가스에 대한 전문 지식과 기술을 충분히 이해한 다음 사용하여야만 고성능화 공정기술이 가능하다. 반도체용 가스는 회로의 집적도가 높아짐에 따라 요구되는 가스의 품질이 점점 고순도화되고 있다. 따라서 현 반도체 공정에 사용되는 가스 순도를 초고순도화 시켜야만 초고집적 소자인 4M DRAM, 16M DRAM, 64M DRAM 제품 개발 및 제조가 가능하다. 다시말해서 공정에 따른 주변조건이 이루어져야 만 반도체 산업이 크게 신장 할 수 있다. 최근 반도체 공정 기술로는 플라즈마(Plasma), 드라이에칭(Dry etching), CVD(Chemical Vapor Deposition), MOCVD(Metal Organic Chemical Vapor Deposition), Ion Implantation, EPI 공정으로 거의 대부분 공정 가스가 가연성, 폭발성, 독성, 부식성 이기 때문에 한번 취급을 잘못하면 막대한 인명 및 재산 피해를 입히므로 취급상 특별한 주의를 요하고 사전에 가스의 전문 지식과 기술을 충분히 이해한 다음 사용하여야 한다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.700-702
• /
• 2009

We present the epitaxial growth of high-quality ZnO layers by chemical vapor transport (CVT) technique on (01-12) sapphire with a ZnO buffer layer growth by metal-organic chemical vapor deposition (MOCVD). The surface of the grown ZnO epitaxial layers has atomically flats and the RMS is 0.11 nm. PL spectrum of as-grown samples exhibits two emissions originated by interactions between photon and free excitons.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.1 no.1
• /
• pp.37-42
• /
• 2000

Copper thin films have been prepared by a metal organic chemical vapor deposition (MOCVD) technology on polyimide and TiN substrates. The Cu-MOCVD technology has advantages of the high deposition rate and the good step coverage compared with the conventional physical vapor deposition (PVD) technology in several industrial applications. The Cu films have been deposited with varying the experimental conditions of substrate temperatures and copper source vapor pressures. The films were annealed in a vacuum condition after the deposition, and the annealing effect on the electrical properties of the films was measured. The crystallinity and the microstructures of the films were observed by scanning electron microscopy (SEM), and the electrical resistivity was measured by 4-point probe. In the case of the Cu deposition on TiN substrate, the best electrical property of the films was measured for the samples prepared at 18$0^{\circ}C$. Very high deposition rate of the Cu film up to 250 nm/min was obtained on the polyimide substrate when the mixture of liquid and vapour precursor was used.

• Korean Journal of Materials Research
• /
• v.33 no.12
• /
• pp.525-529
• /
• 2023

β-Ga₂O₃ has become the focus of considerable attention as an ultra-wide bandgap semiconductor following the successful development of bulk single crystals using the melt growth method. Accordingly, homoepitaxy studies, where the interface between the substrate and the epilayer is not problematic, have become mainstream and many results have been published. However, because the cost of homo-substrates is high, research is still mainly at the laboratory level and has not yet been scaled up to commercialization. To overcome this problem, many researchers are trying to grow high quality Ga₂O₃ epilayers on hetero-substrates. We used diluted SiH4 gas to control the doping concentration during the heteroepitaxial growth of β-Ga₂O₃ on c-plane sapphire using metal organic chemical vapor deposition (MOCVD). Despite the high level of defect density inside the grown β-Ga₂O₃ epilayer due to the aggregation of random rotated domains, the carrier concentration could be controlled from 1 × 10¹⁹ to 1 × 10¹⁶ cm^-3 by diluting the SiH4 gas concentration. This study indicates that β-Ga₂O₃ hetero-epitaxy has similar potential to homo-epitaxy and is expected to accelerate the commercialization of β-Ga₂O₃ applications with the advantage of low substrate cost.