Chemical Vapor Deposition

Nickel oxide films obtained from nickelocene and ozone by atomic layer deposition at 230°C are substoichiometric, but have the crystal structure of NiO. Oxygen can be driven out of the solid by annealing under inert atmosphere, or added into it via aerobic annealing.

A numerical model for the MetalOrganic CVD of alumina from aluminium tri-isopropoxide (ATI), based on an apparent heterogeneous kinetic law was developed using the Computational Fluid Dynamics (CFD) code Fluent. The kinetic parameters were fitted from experimental deposition rates obtained between 360°C and 496°C at a total pressure of 5Torr. Simulated local profiles of alumina deposition rate allowed reproducing the non uniformity of experimental deposition rates due to the dominance of convective gas transport and the depletion of ATI.

The effect of substrate temperature (T_S) on the growth rate, chemical structure, surface morphology, density, refractive index and photoluminescence (PL) of a-SiC:H films is reported. The increase in T_S from 30°C to 400°C causes the elimination of organic moieties from the film and the formation of Si-carbidic network structure. The films produced at high T_S are morphologically homogeneous, dense, and hard materials of high refractive index and extremely low PL intensity.

A new gallium precursor, dimethylgallium isopropoxide (DMGIP), was employed in atomic layer deposition and metalorganic chemical vapor deposition of Ga₂O₃ thin films. DMGIP is a liquid at room temperature with a reasonably high vapor pressure. The characterization of the precursor and thin films of Ga₂O₃ have been performed and DMGIP has been found suitable as gallium precursor for the preparation of Ga₂O₃ films.

A superhydrophobic surface with a water contact angle over 160° has been synthesized in one step starting with a fluorine free precursor by PECVD (low frequency, capacitively coupled). Deposition was carried out on polished silicon wafer, glass plate and hydrophilic macroporous membrane. Water transport of such modified membranes has been studied.

The thermal oxidation of parylene X, poly(ethynyl-p-xylylene-co-p-xylylene), a cross-linkable room-temperature chemical vapor deposited copolymer, is presented and compared to parylene N, poly(p-xylylene), a linear chain crystallizable polymer. The degradation mechanism of the two polymers is much different owing to the cross-linked structure of parylene X.

The MOCVD of cobalt thin films on silicon and silicon dioxide substrates is reported. Cobalt tricarbonyl nitrosyl, cobalt acetylacetonate and cocalt carbonyl are examined as potential precursors, either by liquid or by aerosol delivery. Highly pure and planar Co films are deposited from Co₂(CO)₈ dissolved in dichloromethane. A non-hysteretic GMR behavior in the presence of an externally applied magnetic field normal to the films' surface is also reported.

A vertical hot wall reactor was used to deposit h-BN from borazine as the precursor. By means of static deposition on Si(100) substrates the influence of ammonia addition, precursor concentration, deposition temperature and total gas velocity as well as the structure of the coatings were investigated. Perceptions from this were used to continuously coat SiBNC multifilament fibers in an atmospheric pressure process.

Manganese oxides nanoparticles were synthesized by a chemical vapor process using manganese(0) carbonyl as the precursor. The material synthesis temperatures were varied from 500 to 1500 °C at 200 °C intervals. The physico-chemical properties of MnO_x were analyzed by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), BET surface area, and X-ray photoelectron spectroscopy (XPS).

Two novel parylene polymers poly(α,α′-dimethyl-p-xylylene) and poly(α,α,α′,α′-tetramethyl-p-xylylene)-co-poly(p-xylylene) were deposited at room temperature via the remote pyrolysis, from the ease to synthesize, monomeric-based precursors. The former exhibits equivalent thermal stability to parylene N but is less birefringent, has a lower index of refraction and is soluble.

The thermal oxidative stability of two novel parylene polymers poly(α,α′-dimethyl-p-xylylene) and poly(α,α,α′,α′-tetramethyl-p-xylylene)-co-poly(p-xylylene) were studied as a function of temperature and time at 150 °C. Both α-methylated polymers show superior oxidation resistance in their as-deposited state compared to parylene N as a function of 30 min successive anneals; however, at 150 °C after post-deposition annealing they have inferior oxidation resistance compared to parylene N as a function of time.

In this article is a report of SnO₂ deposition by aerosol-assisted (AA)CVD from tin complexes, [Sn(18-Cr-6)Cl₄] and [Sn(H₂O)₂Cl₄](18-Cr-6). The structure and properties of the precursors, used to synthesize SnO₂ layers by AACVD for the first time, are characterized with the help of X-ray diffraction (XRD), infrared (IR), and thermogravimetric analysis (TGA). Each complex is deposited by AACVD at 250, 400, and 500 °C in a flow of N₂. The resulting films are studied by XRD and atomic force microscopy (AFM). Gas-sensing properties of the deposited layers are tested to 10 ppm NO₂ in air. The maximum sensor response to the analyte is measured at 300 °C.

Presented is a continuous roll-to-roll plasma enhanced chemical vapor deposition process for manufacturing of amorphous SiC barrier coatings on large area web-substrates using a prototype reactor. A key feature is the incorporation of the Penning discharge plasma source to provide magnetically confined, high-density plasma. The developed technology demonstrates significant achievements in barrier performance with water vapor transmission rate of less than 5E-4 g.m⁻²day⁻¹ and durability of BCFs more than 500 hours.

Epitaxial growth by direct liquid injection chemical vapor deposition of nickel ferrite films on MgO (100) and MgAl₂O₄ (100) is demonstrated using Ni(acac)₂ and Fe(acac)₃ (acac=acetylacetonate) in the solvent N,N-dimethyl formamide. This method is attractive for microwave device applications which require relatively thick (>1µm) and topographically smooth films. The dependence of film morphological, structural and magnetic properties on CVD processing conditions is reported.