Pulsed Liquid Injection Chemical Vapor Research Articles

Chemical vapor deposition of entropy-stabilized rock-salt type oxide thin films

Here we present the first synthesis of a multi-cationic oxide (MgCoNiCuZn)O by pulsed liquid injection chemical vapor deposition. The synthesis is performed between 400 °C and 550 °C from five metal–organic precursors simultaneously solubilized in dimethoxyethane (DME). The microstructure of the material was studied using HRTEM with HAADF, SEM, EDS, XPS and XRD before and after annealing.

Nucleation and Growth of Diamond Thin Films: The Role of Temperature and Pressure

AbstractDiamond thin films were deposited onto Si (100) substrates using liquid a solution of water and acetone, ethanol, methanol and commercial Tequila as precursors by the Pulsed Liquid Injection Chemical Vapor Deposition (PLICVD) technique. Temperature was varied from 550 °C to 850 °C. In this work we attempted to find a crystal diameter dependence on temperature and pressure from the experimental data. The goal in this work is to found a function that can be adjusted to the experimental data.

Synthesis of diamond films by pulsed liquid injection chemical vapor deposition using a mixture of acetone and water as precursor

A chemical vapor deposition reactor based on the flash evaporation of an organic liquid precursor was used to grow diamond films on Si substrates. An effective pulsed liquid injection mechanism consisting of an injector, normally used for fuel injection in internal combustion engines, injects micro-doses of the precursor to the evaporation zone at 280 °C and is instantly evaporated. The resulting vapor mixture is transported by a carrier gas to the high-temperature reaction chamber where the diamond nucleates and grows on the substrate surface at temperatures ranging from 750 to 850 °C. The injection frequency, opening time, number of pulses and other injector parameters are controlled by a computer-driven system. The diamond film morphology and structure were characterized by scanning electron microscopy and Raman spectroscopy. The as-deposited diamond films show a ball-shaped morphology with a grain size that varies from 100 to 400 nm, as well as the characteristic diamond Raman band at 1332 cm − 1 . The effects of the experimental parameters and operation principle on the diamond films quality are analyzed and discussed in terms of crystallinity, composition, structure, and morphology.

Chemical vapor deposition of chalcogenide materials for phase-change memories

Films of chalcogenide Ge–Sb–Te materials were grown by pulsed liquid injection chemical vapor deposition (CVD) technique. Simple thermal CVD without additional process activation and CVD with remote activation of precursor decomposition process by a hot-wire were investigated and compared. Ge(NMe 2) 4, Sb(NMe 2) 3 and Te(i-Pr) 2 precursors in a form of diluted solutions in toluene were used for depositions. Film composition was controlled by injection parameters, while the thickness was directly related with number of pulses. Hot-wire activated CVD process allows the growth of chalcogenide films of clearly better quality compared to films grown by standard thermal CVD. Uniform, smooth, crystalline Ge 2Sb 2Te 5 films were grown at substrate/wire temperature 300 °C/550 °C and pressure ⩽ 15 Torr, using nitrogen as a carrier gas, on Si, Si/SiO 2, Si/Si 3N 4 and glass substrates. Forty to forty five nanometer thick films on Si/SiO 2 substrates showed reversible electrical and optical phase switching behavior.

Synthesis of diamond films from organic compounds by Pulsed Liquid Injection CVD

Diamond films were deposited onto Si substrates by Pulsed Liquid Injection Chemical Vapor Deposition (PLICVD) by the flash evaporation of small micro-doses of acetone, ethanol and methanol into the evaporation zone, at 280 °C. The resulting vapor mixture is transported by a carrier gas into the high-temperature reaction chamber, where the diamonds nucleate and grow onto the substrate at 850 °C. The films, characterized by Raman spectroscopy and Scanning Electron Microscopy, show ball-shaped structures in the 200 to 500 nm range, as well as the characteristic Raman diamond band at 1332 cm − 1 . The effect of the experimental parameters is analyzed and discussed in terms of their crystallinity, composition, structure and morphology.

Nucleation and Growth of Titania Nanoparticles Prepared by Pulsed Injection Metal Organic Chemical Vapor Deposition from a Single Molecular Precursor

Nanometer‐sized titania particles were deposited by the pulsed liquid injection chemical vapor deposition technique from a single molecular metal‐organic precursor. A liquid solution of titanium (IV) isopropoxide was used, Ar was the carrier gas, and titania nanoparticles were deposited on the hot wall of the reactor fused quartz tube, under supersaturated conditions. Energy‐dispersive spectroscopy, X‐ray diffraction (XRD), and transmission electron microscopy studies reveal the formation of amorphous titania‐agglomerated nanoparticles (40–50 nm). XRD patterns after different post‐annealing processes reveal a high anatase–rutile transformation temperature, comparable to that of micrometer‐sized titania, attributed to lattice strains in the nanoparticle structure, as calculated from the X‐ray data. The growth dynamics involved in the nucleation and formation of titania nanoparticles is discussed in terms of the so‐called chemical vapor synthesis or chemical vapor condensation.

Magnetic behavior of cobalt oxide films prepared by pulsed liquid injection chemical vapor deposition from a metal-organic precursor

Thin films of cobalt oxide were prepared by the pulsed liquid injection chemical vapor deposition technique from metal-organic precursor. By using a β-diketonate complex of cobalt, namely cobalt (II) acetylacetonate (Co(acac) 2) as the precursor, oxygen as the reactant and argon as the carrier gas, cobalt oxide films 100 nm in thick were deposited onto Si (100) substrates at 650 °C in about 40 min. According to the characterization by X-ray diffraction and atomic force microscopy, smooth and polycrystalline films, consisting exclusively of the Co 3O 4 phase, were deposited. Magnetic properties, such as saturation magnetization, the remanence, the coercivity, the squareness ratio and the switching field distribution, were extracted from the hysteresis loop. Cobalt oxide films with coercivities of 6.61 mT, squareness ratio of 0.2607 and saturation magnetization of 12.17 nA m 2, corresponding to a soft magnetic material, were achieved.