• Title, Summary, Keyword: Metal oxide chemical vapor deposition

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Selective Growth of Nanosphere Assisted Vertical Zinc Oxide Nanowires with Hydrothermal Method

  • Lee, Jin-Su;Nam, Sang-Hun;Yu, Jung-Hun;Yun, Sang-Ho;Boo, Jin-Hyo
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.252.2-252.2
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    • 2013
  • ZnO nanostructures have a lot of interest for decades due to its varied applications such as light-emitting devices, power generators, solar cells, and sensing devices etc. To get the high performance of these devices, the factors of nanostructure geometry, spacing, and alignment are important. So, Patterning of vertically- aligned ZnO nanowires are currently attractive. However, many of ZnO nanowire or nanorod fabrication methods are needs high temperature, such vapor phase transport process, metal-organic chemical vapor deposition (MOCVD), metal-organic vapor phase epitaxy, thermal evaporation, pulse laser deposition and thermal chemical vapor deposition. While hydrothermal process has great advantages-low temperature (less than $100^{\circ}C$), simple steps, short time consuming, without catalyst, and relatively ease to control than as mentioned various methods. In this work, we investigate the dependence of ZnO nanowire alignment and morphology on si substrate using of nanosphere template with various precursor concentration and components via hydrothermal process. The brief experimental scheme is as follow. First synthesized ZnO seed solution was spun coated on to cleaned Si substrate, and then annealed $350^{\circ}C$ for 1h in the furnace. Second, 200nm sized close-packed nanospheres were formed on the seed layer-coated substrate by using of gas-liquid-solid interfacial self-assembly method and drying in vaccum desicator for about a day to enhance the adhesion between seed layer and nanospheres. After that, zinc oxide nanowires were synthesized using a low temperature hydrothermal method based on alkali solution. The specimens were immersed upside down in the autoclave bath to prevent some precipitates which formed and covered on the surface. The hydrothermal conditions such as growth temperature, growth time, solution concentration, and additives are variously performed to optimize the morphologies of nanowire. To characterize the crystal structure of seed layer and nanowires, morphology, and optical properties, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and photoluminescence (PL) studies were investigated.

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Characterization of Ultra Low-k SiOC(H) Film Deposited by Plasma-Enhanced Chemical Vapor Deposition (PECVD)

  • Kim, Sang-Yong
    • Transactions on Electrical and Electronic Materials
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    • v.13 no.2
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    • pp.69-72
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    • 2012
  • In this study, deposition of low-dielectric constant SiOC(H) films by conventional plasma-enhanced chemical vapor deposition (PECVD) were investigated through various characterization techniques. The results show that, with an increase in the plasma power density, the relative dielectric constant (k) of the deposited films decreases whereas the refractive index increases. This is mainly due to the incorporation of organic molecules with $CH_3$ group into the Si-O-Si cage structure. It is as confirmed by FT-IR measurements in which the absorption peak at 1,129 $cm^{-1}$ corresponding to Si-O-Si cage structure increases with power plasma density. Electrical characterization reveals that even after fast thermal annealing process, the leakage current density of the deposited films is in the order of $10^{-11}$ A/cm at 1.5 MV/cm. The reliability of the SiOC(H) film is also further characterized by using BTS test.

Study on Characteristics of 4H-SiC MOS Device with PECVD SiON Insulator (PECVD SiON 절연막을 이용한 4H-SiC MOS 소자 특성 연구)

  • Kim, Hyun-Seop;Lee, Jae-Gil;Lim, Jongtae;Cha, Ho-Young
    • Journal of IKEEE
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    • v.22 no.3
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    • pp.706-711
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    • 2018
  • In this work, we have investigated the characteristics of 4H-SiC metal-oxide-semiconductor (MOS) devices with silicon oxynitride (SiON) insulator using plasma enhanced chemical vapor deposition (PECVD). After post metallization annealing, the trap densities of the fabricated devices decreased significantly. In particular, the device annealed at $500^{\circ}C$ in forming gas ambient exhibited excellent MOS characteristics along with negligible hysteresis, which proved the potential of PECVD SiON as an alternative gate insulator for use in 4H-SiC MOS device.

Non-stoichiometric AlOx Films Prepared by Chemical Vapor Deposition Using Dimethylaluminum Isopropoxide as Single Precursor and Their Non-volatile Memory Characteristics

  • Lee, Sun-Sook;Lee, Eun-Seok;Kim, Seok-Hwan;Lee, Byung-Kook;Jeong, Seok-Jong;Hwang, Jin-Ha;Kim, Chang-Gyoun;Chung, Taek-Mo;An, Ki-Seok
    • Bulletin of the Korean Chemical Society
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    • v.33 no.7
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    • pp.2207-2212
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    • 2012
  • Dimethylaluminum isopropoxide (DMAI, $(CH_3)_2AlO^iPr$) as a single precursor, which contains one aluminum and one oxygen atom, has been adopted to deposit non-stoichiometric aluminum oxide ($AlO_x$) films by low pressure metal organic chemical vapor deposition without an additional oxygen source. The atomic concentration of Al and O in the deposited $AlO_x$ film was measured to be Al:O = ~1:1.1 and any serious interfacial oxide layer between the film and Si substrate was not observed. Gaseous by-products monitored by quadruple mass spectrometry show that ${\beta}$-hydrogen elimination mechanism is mainly contributed to the $AlO_x$ CVD process of DMAI precursor. The current-voltage characteristics of the $AlO_x$ film in Au/$AlO_x$/Ir metalinsulator-metal (MIM) capacitor structure show high ON/OFF ratio larger than ${\sim}10^6$ with SET and RESET voltages of 2.7 and 0.8 V, respectively. Impedance spectra indicate that the switching and memory phenomena are based on the bulk-based origins, presumably the formation and rupture of filaments.

Ultrahigh supercapacitance in cobalt oxide nanorod film grown by oblique angle deposition technique

  • Kannan, V.;Choi, Jong-Hyeok;Park, Hyun-Chang;Kim, Hyun-Seok
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1399-1402
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    • 2018
  • Nanorod films of cobalt oxide ($Co_3O_4$) have been grown by a unique oblique angle deposition (OAD) technique in an e-beam evaporator for supercapacitor electrode applications. This technique offers a non-chemical route to achieve large aspect ratio nanorods. The fabricated electrodes at OAD $80^{\circ}$ exhibited a specific capacitance of 2875 F/g. The electrochemically active surface area was $1397cm^{-2}$, estimated from the non-Faradaic capacitive current region. Peak energy and power densities obtained for $Co_3O_4$ nanorods were 57.7 Wh/Kg and 9.5 kW/kg, respectively. The $Co_3O_4$ nanorod electrode showed a good endurance of 2000 charge-discharge cycles with 62% retention. The OAD approach for fabricating supercapacitor nanostructured electrodes can be exploited for the fabrication of a broad range of metal oxide materials.

Excellent properties of Indium Tin Oxide-Carbon Nano tube Nano composites at low temperatures by Nano Cluster Deposition technique

  • Pammi, S.V.N.;Park, Jong-Hyun;Chanda, Anupama;Park, Yeon-Woong;Ahn, Jun-Ku;Yoon, Soon-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.7-7
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    • 2010
  • Indium tin oxide (ITO) - SWNT nano crystalline composites was synthesized at low temperature(${\sim}250^{\circ}C$)using Nano Cluster Deposition technique by Metal Orhoganic Chemical Vapor Deposition method. XRD patterns of ITO- SWNT composite shows pure cubic phases without any secondary phase. I-V measurement gives resistance of 12 ohms for Sn doped (3 wt %) indium oxide-SWNT composites. The electrical conductivity of the nano composites is significantly enhanced compared to the SWNT.

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Recent Development in Metal Oxides for Carbon Dioxide Capture and Storage (금속 산화물을 기반으로 한 이산화탄소 포집과 저장에 대한 최근 기술)

  • Oh, Hyunyoung;Patel, Rajkumar
    • Membrane Journal
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    • v.30 no.2
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    • pp.97-110
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    • 2020
  • CO2 capture and storage (CCS) is one of the promising technologies that can mitigate ever-growing emission of anthropogenic carbon dioxide and resultant climate change. Among them, chemical looping combustion (CLC) and calcium looping (CaL) are getting increasing attention recently as the prospective alternatives to the existing amine scrubbing. Both methods use metal oxides in the process and consist of cyclic reactions. Yet, due to their cyclic nature, they both need to resolve sintering-induced cyclic stability deterioration. Moreover, the structure of the metal oxides needs to be optimized to enhance the overall performance of CO2 capture and storage. Deposition of thin film coating on the metal oxide is another way to get rid of wear and tear during the sintering process. Chemical vapor deposition or atomic layer deposition are the well-known, established methods to form thin film membranes, which will be discussed in this review. Various effective recent developments on structural modification of metal oxide and incorporation of stabilizers for cyclic stability are also discussed.

Deposition and Characterization of $HfO_2/SiNx$ Stack-Gate Dielectrics Using MOCVD (MOCVD를 이용한 $HfO_2/SiNx$ 게이트 절연막의 증착 및 물성)

  • Lee Taeho;Oh Jaemin;Ahn Jinho
    • Journal of the Microelectronics and Packaging Society
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    • v.11 no.2
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    • pp.29-35
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    • 2004
  • Hafnium-oxide gate dielectric films deposited by a metal organic chemical vapor deposition technique on a $N_2-plasma$ treated SiNx and a hydrogen-terminated Si substrate have been investigated. In the case of $HfO_2$ film deposited on a hydrogen-terminated Si substrate, suppressed crystallization with effective carbon impurity reduction was obtained at $450^{\circ}C$. X-ray photoelectron spectroscopy indicated that the interface layer was Hf-silicate rather than phase separated Hf-silicide and silicon oxide structure. Capacitance-voltage measurements show equivalent oxide thickness of about 2.6nm for a 5.0 nm $HfO_2/Si$ single layer capacitor and of about 2.7 nm for a 5.7 nm $HfO_2/SiNx/Si$ stack capacitor. TEM shows that the interface of the stack capacitor is stable up to $900^{\circ}C$ for 30 sec.

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Dielectric properties of Pr$_2$O$_3$ high-k films grown by metalorganic chemical vapor deposition on silicon

  • Nigro, Raffaella-Lo;Vito Raineri;Corrado Bongiomo
    • Electrical & Electronic Materials
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    • v.16 no.9
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    • pp.65.2-65
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    • 2003
  • Praseodymium oxid ($Pr_2$$O_3$) thin films have been deposited on Si(100) substrates by metalorganic chemical vapor deposition using praseodymium tris-2,2,6,6-tetramethyl-3,5-heptandionate as source material. Film structural, morphological, and compositional characterizations have been carried out. Dielectric properties have been studied as well by capacitance-voltage and current-voltage measurements on metal-oxide-semiconductor capacitors of several areas. The $Pr_2$$O_3$ films have shown a dielectric constant = 23-25 and a leakage current density of $8.8{\times}10$-e $A/\textrm{mm}^2$ at +1 V.

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Resistance Switching Mechanism of Metal-Oxide Nano-Particles Memory on Graphene Layer

  • Lee, Dong-Uk;Kim, Dong-Wook;Kim, Eun-Kyu
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.318-318
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    • 2012
  • A graphene layer is most important materials in resent year to enhance the electrical properties of semiconductor device due to high mobility, flexibility, strong mechanical resistance and transparency[1,2]. The resistance switching memory with the graphene layer have been reported for next generation nonvolatile memory device[3,4]. Also, the graphene layer is able to improve the electrical properties of memory device because of the high mobility and current density. In this study, the resistance switching memory device with metal-oxide nano-particles embedded in polyimide layer on the graphene mono-layer were fabricated. At first, the graphene layer was deposited $SiO_2$/Si substrate by using chemical vapor deposition. Then, a biphenyl-tetracarboxylic dianhydride-phenylene diamine poly-amic-acid was spin coated on the deposited metal layer on the graphene mono-layer. Then the samples were cured at $400^{\circ}C$ for 1 hour in $N_2$ atmosphere after drying at $135^{\circ}C$ for 30 min through rapid thermal annealing. The deposition of aluminum layer with thickness of 200 nm was done by a thermal evaporator. The electrical properties of device were measured at room temperature using an HP4156a precision semiconductor parameter analyzer and an Agilent 81101A pulse generator. We will discuss the switching mechanism of memory device with metal-oxide nano-particles on the graphene mono-layer.

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