Deposition of Ceramic Films by A Novel Pulsed-Gas Mocvd Technique

1992 ◽  
Vol 271 ◽  
Author(s):  
Kenneth A. Aitchison ◽  
James D. Barrie ◽  
Joseph Ciofalo
Keyword(s):  
Gas Phase ◽  
Film Growth ◽  
Flow Reactor ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Film Deposition ◽  
Organic Chemical ◽  
Oxide Systems ◽  
Metal Organic ◽  
Mocvd Technique

ABSTRACTMetal-Organic Chemical Vapor Deposition (MOCVD) is a versatile technique for the deposition of thin films of metals, semiconductors and ceramics. Commonly used hot wall flow-reactor designs suffer from a number of limitations. Chemical processes occurring in these reactors typically include a combination of homogeneous (gas-phase) and heterogeneous (gas-surface) reactions. These complex conditions are difficult to model and are poorly understood. In addition, flow reactors use large quantities of expensive precursor materials and are not well suited to the formation of abrupt interfaces. We report here a novel MOCVD technique which addresses these problems and enables a more thorough mechanistic understanding of the heterogeneous decomposition pathways of metal-organic compounds. This technique, the low-pressure pulsed gas method, has been demonstrated to provide high deposition rates with excellent control over film thickness. The deposition conditions effectively eliminate homogeneous processes allowing surface-mediated reactions to dominate. This decoupling of gas-phase chemistry from film deposition allows a better understanding of reaction mechanisms and provides better control over film growth. Both single metal oxides and binary oxide systems have been investigated on a variety of substrate materials. Effects of precursor chemistry, substrate surface, temperature and pressure on film composition and morphology will be discussed.

Computational Study of Pulsed Metal-Organic Chemical Vapor Deposition of Aluminum Nitride

2011 ◽  
Author(s):  
Derek Endres ◽  
Sandip Mazumder
Keyword(s):  
Gas Phase ◽  
Gas Flow ◽  
Film Growth ◽  
Chemical Vapor ◽  
Particle Formation ◽  
Organic Chemical ◽  
Group V ◽  
Group Iii ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Particles of aluminum nitride (AlN) have been observed to form during epitaxial growth of AlN films by metal organic chemical vapor deposition (MOCVD). Particle formation is undesirable because particles do not contribute to the film growth, and are detrimental to the hydraulic system of the reactor. It is believed that particle formation is triggered by adducts that are formed when the group-III precursor, namely tri-methyl-aluminum (TMAl), and the group-V precursor, namely ammonia (NH3), come in direct contact in the gas-phase. Thus, one way to eliminate particle formation is to prevent the group-III and the group-V precursors from coming in direct contact at all in the gas-phase. In this article, pulsing of TMAl and NH3 is numerically investigated as a means to reduce AlN particle formation. The investigations are conducted using computational fluid dynamics (CFD) analysis with the inclusion of detailed chemical reaction mechanisms both in the gas-phase and at the surface. The CFD code is first validated for steady-state (non-pulsed) MOCVD of AlN against published data. Subsequently, it is exercised for pulsed MOCVD with various pulse widths, precursor gas flow rates, wafer temperature, and reactor pressure. It is found that in order to significantly reduce particle formation, the group-III and group-V precursors need to be separated by a carrier gas pulse, and the carrier gas pulse should be at least 5–6 times as long as the precursor gas pulses. The studies also reveal that with the same time-averaged precursor gas flow rates as steady injection (non-pulsed) conditions, pulsed MOCVD can result in higher film growth rates because the precursors are incorporated into the film, rather than being wasted as particles. The improvement in growth rate was noted for both horizontal and vertical reactors, and was found to be most pronounced for intermediate wafer temperature and intermediate reactor pressure.

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.

Effect of Incubation Time on Deposition Behavior of Ruthenium Films by MOCVD Using (2,4-Dimethylpentadienyl)(Ethylcyclopentadienyl)Ruthenium

2009 ◽  
Vol 421-422 ◽  
pp. 87-90 ◽  
Author(s):  
Masaki Hirano ◽  
Kazuhisa Kawano ◽  
Hiroshi Funakubo
Keyword(s):  
Incubation Time ◽  
Deposition Temperature ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Native Oxide ◽  
Organic Chemical ◽  
Deposition Mechanism ◽  
Deposition Amount ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

The deposition mechanism of metal-Ru films including incubation time was investigated for Ru films prepared by metal organic chemical vapor deposition from (2,4-Dimethylpentadienyl)(ethylcyclopentadienyl)Ruthenium (DER) - O2 system. Substrates with amorphous top-layer having various Hf/Si ratio, SiO2 (native oxide)/(001)Si (SiO2), HfSiON/SiON/(001)Si (HfSiON) and HfO2/SiON/(001)Si (HfO2), were used as substrates. The deposition temperature dependence of the deposition amount at the fixed deposition time ranging from 210 oC to 300 oC revealed that the deposition amount depended on the deposition temperature below 250 oC, while it was almost constant above this temperature. Incubation time depended on the kinds of substrate at 210 oC and the substrate surface was fully covered in a shorter time with smaller deposition amount for the substrates with shorter incubation time. In addition, the film with shorter incubation time had smaller surface roughness.

Thin films for superconducting electronics: Precursor performance issues, deposition mechanisms, and superconducting phase formation-processing strategies in the growth of Tl2Ba2CaCu2O8 films by metal-organic chemical vapor deposition

1997 ◽  
Vol 12 (5) ◽  
pp. 1214-1236 ◽  
Author(s):  
Bruce J. Hinds ◽  
Richard J. McNeely ◽  
Daniel B. Studebaker ◽  
Tobin J. Marks ◽  
Timothy P. Hogan ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Pressure ◽  
Vapor Deposition ◽  
Film Growth ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Epitaxial Tl2Ba2CaCu2O8 thin films with excellent electrical transport characteristics are grown in a two-step process involving metal-organic chemical vapor deposition (MOCVD) of a BaCaCuO(F) thin film followed by a postanneal in the presence of Tl2O vapor. Vapor pressure characteristics of the recently developed liquid metal-organic precursors Ba(hfa)2 • mep (hfa = hexafluoroacetylacetonate, mep = methylethylpentaglyme), Ca(hfa)2 • tet (tet = tetraglyme), and the solid precursor Cu(dpm)2 (dpm = dipivaloylmethanate) are characterized by low pressure thermogravimetric analysis. Under typical film growth conditions, transport is shown to be diffusion limited. The transport rate of Ba(hfa)2 • mep is demonstrated to be stable for over 85 h at typical MOCVD temperatures (120 °C). In contrast, the vapor pressure stability of the commonly used Ba precursor, Ba(dpm)2, deteriorates rapidly at typical growth temperatures, and the decrease in vapor pressure is approximately exponential with a half-life of ∼9.4 h. These precursors are employed in a low pressure (5 Torr) horizontal, hot-wall, film growth reactor for growth of BaCaCuO(F) thin films on (110) LaAlO3 substrates. From the dependence of film deposition rate on substrate temperature and precursor partial pressure, the kinetics of deposition are shown to be mass-transport limited over the temperature range 350–650 °C at a 20 nm/min deposition rate. A ligand exchange process which yields volatile Cu(hfa)2 and Cu(hfa) (dpm) is also observed under film growth conditions. The MOCVD-derived BaCaCuO(F) films are postannealed in the presence of bulk Tl2Ba2CaCu2O8 at temperatures of 720–890 °C in flowing atmospheres ranging from 0–100% O2. The resulting Tl2Ba2CaCu2O8 films are shown to be epitaxial by x-ray diffraction and transmission electron microscopic (TEM) analysis with the c-axis normal to the substrate surface, with in-plane alignment, and with abrupt film-substrate interfaces. The best films exhibit a Tc = 105 K, transport-measured Jc= 1.2 × 105 A/cm2 at 77 K, and surface resistances as low as 0.4 mΩ (40 K, 10 GHz).

Simulation and Suppression of the Gas Phase Pre-reaction in Metal-Organic Chemical Vapor Deposition of ZnO

2011 ◽  
Vol 28 (11) ◽  
pp. 116803 ◽  
Author(s):  
Guang-Yao Zhu ◽  
Shu-Lin Gu ◽  
Shun-Ming Zhu ◽  
Kun Tang ◽  
Jian-Dong Ye ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

The relationship between the MOCVD parameters and the crystallinity, epitaxy, and domain structure of PbTiO3 films

1994 ◽  
Vol 9 (1) ◽  
pp. 156-163 ◽  
Author(s):  
G.R. Bai ◽  
H.L.M. Chang ◽  
C.M. Foster ◽  
Z. Shen ◽  
D.J. Lam
Keyword(s):  
Gas Phase ◽  
Deposition Temperature ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Surface Orientation ◽  
Organic Chemical ◽  
Epitaxial Relationship ◽  
Domain Structures ◽  
Vapor Deposition Technique ◽  
The Relationship

Lead- and titanium-based oxide thin films were prepared by the metal-organic chemical vapor deposition technique (MOCVD) and the relationship between the film structures and the processing parameters, such as the ratio of Pb/Ti precursors in the gas phase, substrate materials, substrate surface orientation, and growth temperature, was systematically studied. It was found that whether a single-phase stoichiometric PbTiO3 film could be obtained depended on both the Pb/Ti precursor ratio in the gas phase and the deposition temperature. Under appropriate conditions, stoichiometric PbTiO3, films could be obtained on all the substrates including silicon, MgO, α-Al2O3, SrTiO3, and LaAlO3. The PbTiO3 films grown on silicon substrates were always polycrystalline, whereas epitaxial PbTiO3 films were obtainable on all the other substrates. For epitaxial PbTiO3 films, the epitaxial relationship, crystallinity, and domain structures were found to be a function of both the substrate materials and surface orientation as well as the deposition temperature. X-ray rocking curves (ω scan) of the (100) and (001) planes of PbTiO3 epitaxial film and PbTiO3 single crystal revealed the inherent nature of the domain structures in PbTiO3.

GeSn Film Deposition Using Metal Organic Chemical Vapor Deposition

2013 ◽  
Vol 53 (1) ◽  
pp. 245-250 ◽  
Author(s):  
K. Suda ◽  
T. Uno ◽  
T. Miyakawa ◽  
H. Machida ◽  
M. Ishikawa ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Film Deposition ◽  
Organic Chemical ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Excimer Laser-Induced Deposition of InP and Indium-Oxide Films

1983 ◽  
Vol 29 ◽  
Author(s):  
V. M. Donnelly ◽  
M. Geva ◽  
J. Long ◽  
R. F. Karlicek
Keyword(s):  
Gas Phase ◽  
Excimer Laser ◽  
Oxide Films ◽  
Chemical Vapor ◽  
Normal Incidence ◽  
Organic Chemical ◽  
Organic Precursor ◽  
Composition Control ◽  
Metal Organic ◽  
Carbon Inclusion

ABSTRACTInP and In-oxide films have been deposited on quartz, GaAs, and InP substrates by excimer laser-induced photodecomposition of (CH3)3InP(CH3)3 and P(CH3)3 vapors at 193 nm. The oxide film refractive index and stoichiometry are close to In2O3. Phosphorus incorporation in the films was greatly enhanced by focusing the laser beam to promote multiple-photon dissociation processes. These conditions also lead to enhanced carbon inclusion in the films, due to formation of species such as CH and CH2 in the gas phase. However, this carbon inclusion could be suppressed by focusing the beam onto the surface at normal incidence. In the irradiated zone InP could be deposited with P(CH3)3-to-(CH3)3InP(CH3)3 ratios of only ∼1:1. The technique offers several potential advantages over conventional metal-organic chemical vapor deposition (MOCVD), including lower temperature, enhanced rates, safer gases, and threedimensional film composition control.Strong atomic In emission is observed in the gas-phase above the depositing film, due to a multiple photon dissociation process. Gasphase fluorescence from P, CH, and C was also observed. These emissions give insight into the photodecomposition mechanism and also serve as a monitor of metal-organic precursor concentrations.

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