Alexander M. Wrobel

Reactivity of Alkylsilanes and Alkylcarbosilanes in Atomic Hydrogen‐Induced Chemical Vapor Deposition

A number of alkylsilanes and alkylcarbosilanes of widely different molecular structure are characterized in terms of their ability to the formation of amorphous hydrogenated silicon-carbon (a-Si:C:H) film in atomic hydrogen-induced chemical vapor deposition. The compounds containing only the Si-C bonds or four-membered carbosilane rings appear to be inactive, while those with the Si-Si or Si-H bonds are capable of the a-Si:C:H film-formation. The reactivity of the latter group of compounds is characterized by the deposition yield parameter determined at the constant and variable feeding rates. Based upon the reactivity data a mechanism for the initiation step is proposed.

Atomic hydrogen-induced chemical vapor deposition of a-Si:C:H thin-film materials from alkylsilane precursors

Amorphous hydrogenated silicon-carbon films (a-Si:C:H) were produced by atomic hydrogen-induced chemical vapor deposition (CVD) using hexamethyldisilane (HMDS) and tetrakis(trimethylsilyl)silane (TMSS) as a single-source compounds. The CVD process has been examined in terms of the mechanism of the activation step. The susceptibility of particular bonds in the source compounds towards reaction with atomic hydrogen is characterized. The effect of substrate temperature (Ts) on the deposition rate, chemical structure, composition, surface morphology, as well as optical properties of the films, such as refractive index, optical band gap and photoluminescence, has been investigated. The increase of Ts from 30 to 400 °C causes the elimination of organic moieties from the film and the formation of compositionally and morphologically homogeneous inorganic material of Sicarbidic structure. The investigated optical properties of the film can be controlled by its stoichiometry or deposition temperature.

Hard and High-Temperature-Resistant Silicon Carbonitride Coatings Based on N-Silyl-Substituted Cyclodisilazane Rings

l,3-bis(dimethylsilyl)-2,2,4,4-tetrametyhylcyclodisilazane was used as a single-source precursor for the production of silicon carbonitride (SiCN) thin-film coatings by remote microwave hydrogen plasma chemical vapor deposition (RP-CVD). The effect of the substrate temperature (Ts) on the rate and yield of the RP-CVD process, chemical composition, chemical structure, and surface morphology of the resulting film is reported. The temperature dependencies of the thickness-based growth rate and growth yield of the film imply that for the low substrate temperature range (35 ≤ T S < 200°C), film growth is limited by adsorption of film-forming precursors, whereas in the high substrate temperature range (200 ≤ T s ≤ 400°C), film growth is independent of the temperature and RP-CVD is a mass-transport limited process. The increase of the substrate temperature from 35 to 400°C causes the elimination of organic moieties from the film and the formation of the Si-C network, which contains incorporated N-silyl-substituted cyclodisilazane molecular skeletons of the precursor linked with the network via the Si-C bonds. The microscopic examination revealed that the films are defect-free materials of excellent morphological homogeneity and exhibit small surface roughness, which vary in a narrow range of values. The SiCN films deposited at various substrate temperatures were characterized in terms of their density, adhesion to a substrate, hardness, elastic modulus, and friction coefficient. The film properties are strongly influenced by the compositional and structural parameters represented, respectively, by the contents of nitrogen and Si-C bonds; the latter described by the relative integrated intensity of the Si-C infrared band. The reasonable relationships between the film properties and the mentioned compositional and structural parameters have been determined.

High-quality amorphous hydrogenated silicon carbide coatings by remote plasma chemical vapor deposition from a single-source precursor

Abstract The amorphous hydrogenated silicon carbide (a-SiC:H) films were produced by the remote hydrogen plasma chemical vapor deposition (CVD) using tetrakis(trimethylsilyl)silane (TMSS) molecular cluster as a novel single-source precursor. The remote plasma CVD process has been examined in terms of mechanism of the activation step. The determined temperature dependence of the film deposition rate suggests that the examined remote hydrogen plasma CVD is a non-thermally activated process. The susceptibility of particular bonds in TMSS molecule to the activation step has been characterized using suitable model source compounds. The films have been characterized by ellipsometry, Auger electron spectroscopy, scanning electron microscopy, and reflection high energy electron diffraction analysis. There is reported the effect of substrate temperature (T s ) on such properties of the film as the compositional uniformity, surface morphology, and refractive index. The films exhibit an excellent morphological homogeneity, outstanding compositional uniformity and stoichiometry near pure silicon carbide at T s = 300–400°C. The refractive index alters from 1.5 to 2.4 with rising T s in the range of 30–400°C.