Room Temperature Ferromagnetic Properties of Epitaxially Grown Zn1-xCoxO Thin Films

2004 ◽  
Vol 834 ◽  
Author(s):  
F. Yun ◽  
Varatharajan Rengarajan ◽  
J. Nause ◽  
H. Morkoç
Keyword(s):  
Thin Films ◽  
Quantum Interference ◽  
Gas Flow ◽  
Magnetic Hysteresis ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Ferromagnetic Behavior ◽  
Zero Field ◽  
Metal Organic ◽  
Carrier Gas Flow

ABSTRACTWe have conducted a systematic magnetic characterization of a series of Zn1-xCoxO samples with different cobalt composition. The Zn1-xCoxO thin films were epitaxially grown by metal organic chemical vapor deposition (MOCVD) on quartz and ZnO substrates. The Co composition was adjusted by controlling the bubbler temperature and carrier gas flow. The magnetization measurements were performed using a Quantum Design MPMS system, which utilizes a superconducting quantum interference device (SQUID) magnetometer. Magnetic hysteresis curves were observed at 5K which persisted up to 300K, possibly characteristic of ferromagnetic behavior. Temperature dependent magnetization was recorded under both zero-field cooled (ZFC) and field cooled (FC) conditions. Changes of magnetization were observed under ZFC and FC conditions in some samples from 5K up to 300K. Composition-dependent changes in magnetization were also observed among samples with different cobalt doping, indicative of ferromagnetism related directly to cobalt incorporation. Magnetic field dependent magnetization at various temperatures with field up to 5 Tesla suggests the Zn1-xCoxO layers were not paramagnetic.

Copper Films Prepared by Metal Organic Chemical Vapor Deposition (MOCVD) Process Using Copper (Acetylacetonate) and Water Vapor as Reactants: The Impact of Water Vapor

1992 ◽  
Vol 282 ◽  
Author(s):  
Yu-Neng Chang
Keyword(s):  
Water Vapor ◽  
Partial Pressure ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Gas Flow Rate ◽  
Cu Films ◽  
Metal Organic ◽  
Carrier Gas Flow ◽  
Organic Chemical Vapor Deposition

ABSTRACTBy using the strong reductive potential of copper acetylacetone (Cu(acac)2) when Cu(acac)2) was thermally decomposed, copper metal films were prepared by metal organic chemical vapor deposition (MOCVD) process using sublimed Cu(acac)2 vapor and water vapor as reactants, at one atmosphere pressure. According to thermodynamic calculations, Cu films could be prepared by MOCVD process with a high ratio of partial pressures for water vapor and Cu(acac)2 vapor (PH2O/Pcu(acac)2>30) In this paper, the impacts of MOCVD processing parameters such as watervapor partial pressure, total carrier gas flow rate, and precursor partial pressure on film composition and microstructure were investigated. Deposition temperature is the primary processing parameter affecting film stoichiometry. In a specific deposition temperature window, from 370°C to 400°C, polycrystalline Cu films with Cu [111] preferential orientation were deposited. ER and XRD results indicated that films deposited at temperature lower than 350°C contain copper oxide phase with poor crystal structure. By comparing the values of X-ray Auger Electron Spectroscopy (XAES) and Auger parameter (αAu) from photoelectrons of Cu films and standards from reference compounds, die principle oxidation state of copper in these films was determined as Cu(0). The deposition results indicated that a water vapor partial pressure above 10 torr is necessary to produce Cu films. As indicated by SEM, Increasing the carrier gas flow rate, above 600 sccm, can reduce the average temperature profile in the thermal boundary layer above the substrate surface, retard the gas phase reaction rate, presumably eliminate the homogeneous nucleation, and deposit smooth Cu films.

RuO2 films by metal-organic chemical vapor deposition

1993 ◽  
Vol 8 (10) ◽  
pp. 2644-2648 ◽  
Author(s):  
Jie Si ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Film Structure ◽  
Organic Chemical ◽  
Dilute Gas ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Pure and conducting RuO2 thin films were successfully deposited on Si, SiO2/Si, and quartz substrates at temperatures as low as 550 °C by a hot wall metal-organic chemical vapor deposition (MOCVD). Bis(cyclopentadienyl)ruthenium, Ru(C5H5)2, was used as the precursor. An optimized MOCVD process for conducting RuO2 thin films was established. Film structure was dependent on MOCVD process parameters such as bubbler temperature, dilute gas flow rates, deposition temperature, and total pressure. Either pure RuO2, pure Ru, or a RuO2 + Ru mixture was obtained under different deposition conditions. As-deposited pure RuO2 films were specular, crack-free, and well adhered on the substrates. The Auger electron spectroscopy depth profile showed good composition uniformity across the bulk of the films. The MOCVD RuO2 thin films exhibited a resistivity as low as 60 μω-cm. In addition, the reflectance of RuO2 in the NIR region had a metallic character.

Properties of Tin Oxide Films Prepared by MOCVD

2004 ◽  
Vol 449-452 ◽  
pp. 997-1000 ◽  
Author(s):  
Gwang Pyo Choi ◽  
Yong Joo Park ◽  
Whyo Sup Noh ◽  
Jin Seong Park
Keyword(s):  
Thin Films ◽  
Oxygen Content ◽  
Tin Oxide ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition ◽  
Tin Oxide Films ◽  
N2 Annealing

Tin oxide thin films were deposited at 375 °C on α-alumina substrate by metal-organic chemical vapor deposition (MOCVD) process. A number of hillocks on the film were formed after air annealing at 500 °C for 30 min and few things in N2 annealing. The oxygen content and the binding energy after air annealing came to close the stoichiometric SnO2. The cauliflower hillocks of the film seem to be formed by the continuous migration of crystallites from a cauliflower grain on the substrate to release the stress due to the increase of oxygen content and volume.

Transparent conducting indium oxide thin films grown by low-temperature metal organic chemical vapor deposition

2007 ◽  
Vol 515 (5) ◽  
pp. 2921-2925 ◽  
Author(s):  
Chunyu Wang ◽  
Volker Cimalla ◽  
Genady Cherkashinin ◽  
Henry Romanus ◽  
Majdeddin Ali ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Indium Oxide ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Transparent Conducting ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Study on ZrO2:Er Thin Films Fabricated by Metal-Organic Chemical Vapor Deposition

2003 ◽  
Vol 42 (Part 1, No. 5A) ◽  
pp. 2839-2842 ◽  
Author(s):  
Jeong Hoon Park ◽  
Kug Sun Hong ◽  
Woon Jo Cho ◽  
Jang-Hoon Chung
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Metal-organic chemical vapor deposition of ZrO2 films using Zr(thd)4 as precursors

1994 ◽  
Vol 9 (7) ◽  
pp. 1721-1727 ◽  
Author(s):  
Jie Si ◽  
Seshu B. Desu ◽  
Ching-Yi Tsai
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Film Deposition ◽  
Organic Chemical ◽  
Deposition Rates ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition ◽  
Deposited Films

Synthesis of zirconium tetramethylheptanedione [Zr(thd)4] was optimized. Purity of Zr(thd)4 was confirmed by melting point determination, carbon, and hydrogen elemental analysis and proton nuclear magnetic resonance spectrometer (NMR). By using Zr(thd)4, excellent quality ZrO2 thin films were successfully deposited on single-crystal silicon wafers by metal-organic chemical vapor deposition (MOCVD) at reduced pressures. For substrate temperatures below 530 °C, the film deposition rates were very small (⋚1 nm/min). The film deposition rates were significantly affected by (i) source temperature, (ii) substrate temperature, and (iii) total pressure. As-deposited films are carbon free. Furthermore, only the tetragonal ZrO2 phase was identified in as-deposited films. The tetragonal phase transformed progressively into the monoclinic phase as the films were subjected to a high-temperature post-deposition annealing. The optical properties of the ZrO2 thin films as a function of wavelength, in the range of 200 nm to 2000 nm, were also reported. In addition, a simplified theoretical model which considers only a surface reaction was used to analyze the deposition of ZrO2 films. The model predicated the deposition rates well for various conditions in the hot wall reactor.

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