Easily accessible information from quantum chemical computations can be used to predict decomposition barriers for phosphorous and arsenic precursor molecules for CVD. Based on the mechanistic description of the β-hydrogen elimination reaction, a precursor with a very low decomposition barrier is suggested.
Dy2O3 doped ZrO2 films are grown on silicon substrates using atomic layer deposition at 300 °C. Dy(thd)3 (thd = 2,2,6,6-tetramethyl-3,5-heptanedionato) and ZrCl4 are used as metal precursors and H2O as the oxygen precursor. Despite the low growth rate of Dy2O3 in a beta-diketonate/water process, the process allows deposition of thin films with the dysprosium content of few mass %. The films crystallize in the form of tetragonal zirconia already in as-deposited state and grow conformally onto 3D substrates with an aspect ratio of 1:20. The capacitors formed on the basis of the films in as-deposited and annealed states demonstrate current–voltage and capacitance behavior characteristic of those with high-permittivity dielectrics. The maximum concentration of electronic defects at oxide/electrode interfaces reaches 1.8 × 1011 cm−2 eV−1.
A cold-wall CVD system for graphene growth on metal foils is converted to an effectively hot-wall one by merely adding another heater, sandwiching the foil in between the heaters. This simple design demonstrates both an improved temperature uniformity characteristic for hot-wall systems, and a high responsivity distinctive for cold-wall ones. This beneficial combination allows for a much better control of graphene growth kinetics.
The ability of the two fluid method (TFM) to predict the gas-solid flow phenomenon in conical spouted beds operated with high density particles simulating the nuclear fuel coating conditions is investigated.
The effect of substrate temperature (TS) on the growth rate, chemical structure, surface morphology, density, refractive index, and optical absorption of a-SiCO:H films is reported. The increase in TS from 30 °C to 350 °C involves the transformation of the film from polymeric, low-density material to strongly cross-linked, dense Si-oxycarbide ceramics.
Magnesium oxide films are deposited on glass via aerosol-assisted (AA)CVD. Depositions using magnesium acetate tetrahydrate in ethanol or methanol are carried out at 400, 500, and 600 °C. Films are analyzed by various methods. Growth rate, film thickness, and crystallite size increase with temperature, regardless of solvent. The films are crystalline and the crystallographic preferred orientation varies with solvent and temperature, allowing fine-tuning for industrial applications. Solvent and temperature influence the surface morphology; films deposited using ethanol consist of small surface structures compared to the featureless morphology of methanol-derived films. The refractive index of the films is 1.72 for methanol and 1.70 for ethanol systems.
This study compares the effectiveness of two Bi sources, trimethyl bismuth (TMBi) and triethyl bismuth (TEBi), in the growth of GaAs1-yBiy thin films. Through optimization of the growth conditions, GaAs1-yBiy-GaAs heterostructures with high lateral homogeneity of Bi are grown. TEBi results in a lower carbon concentration than is typical of methyl-based compounds when used at low growth temperatures. These findings suggest the process of Bi incorporation proceeds more efficiently using the TEBi precursor. These studies do not show noticeable growth rate reduction under the dilute flows of TMBi and TEBi, however at high Bi source flux, a growth rate drop was observed for both sources.
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