Thermodynamic modeling of the deposition of Si—C—N films from the gas phase during the decomposition of organosilicon compounds

Thermodynamic modeling of the process of chemical vapor deposition (CVD) of SiC_x and SiC_xN_y films from the gas phase was carried out using organosilicon compounds (EtN(SiMe₃)₂, PhN(SiMe₃)₂, and PhSiMe₃) at reactor pressures of 0.01 and 10 Torr in the temperature range of 500–1200 K. It was established that regions of existence of two phase complexes, namely, SiC + Si₃N₄ + C and SiC + C, were present on the CVD diagrams calculated for the EtN(SiMe₃)₂—He and PhN(SiMe₃)₂—He systems. The CVD diagrams calculated for the EtN(SiMe₃)₂—NH₃, PhN(SiMe₃)₂—NH₃, and PhSiMe₃—NH₃ systems have regions of existence of three phase complexes, namely, Si₃N₄ + C, SiC + Si₃N₄ + C, and SiC + C. The composition of the obtained silicon-containing films was calculated.     

Thermodynamic analysis of preparation processes for boron-containing films with the use of N-trimethylborazine and hydrogen

The possibilities for using a minimization program for Gibbs energy functions (G _min) in multiphase multicomponent systems are illustrated. The process of chemical vapor deposition in a B-C-N-H-O system at reduced pressure (13.3 Pa) over a wide range of synthesis temperatures (300–1300 K) with the use of an initial gas mixture of N-trimethylborazine and hydrogen is modeled thermodynamically. The possibility of obtaining films of different compositions is shown, and the boundary conditions for the deposition of coatings of the general composition BC _x N _y are determined.     

Study of the structure of thin nanocrystalline films

Structure and phase composition of thin nanocrystalline films of semiconductors and insulators CdS, Cd_xZn_1?xS, SiC_xN_y, and BC_xN_y were studied using registration of weak diffraction intensities with synchrotron radiation. Three methods were developed and applied to obtain diffraction patterns, namely, θ—2-scan (Bragg—Brentano geometry); 2θ-scan (grazing incidence scheme); a scheme with an image plate as detector. The characteristic features of the diffraction patterns, obtained from the aforementioned samples, are discussed. The X-ray diffraction data are compared with the results obtained by HREM, SAED, electron spectroscopy, ellipsometry, IR and Raman spectroscopy. It is stated that: 1) the films are composed of nanocrystals, their size depending on the conditions of film deposition; 2) single crystalline substrate favors formation of oriented crystals, i.e., of the domains comprising uniformly oriented nanocrystals.     

A study of the chemical bond types in films deposited from bis(trimethylsilyl)-ethylamine by PECVD

Silicon carbonitride films are synthesized by plasma enhanced chemical vapor deposition from bis(trimethylsilyl)ethylamine and helium or ammonium mixtures. The structure of chemical bonds in the films is studied by X-ray photoelectron and IR spectroscopy. The data on the main types of bonds present in silicon carbonitride films deposited under different synthesis conditions are obtained. It is shown that the use of ammonia at a low deposition temperature provides the synthesis of films with a simultaneous formation of Si-C, Si-N, and C-N bonds. The main bonds in films obtained from a bis(trimethylsilyl)ethylamine and helium mixture are Si-C and Si-N. The chemical structure of films obtained at high synthesis temperatures is close to SiC _x regardless of the type of the additional gas used.     

X-ray photoelectron and auger spectroscopic study of the chemical composition of BC<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>N<Subscript><Emphasis Type="Italic">y</Emphasis></Subscript> films

X-ray photoelectron and Auger spectroscopy are used to investigate the chemical composition of BC _x N _y films synthesized by PECVD from different initial gas mixtures in the temperature range 473–723 K. Main principles and features of the film formation are found. It is shown that the chemical composition of BC _x N _y films significantly depends on the synthesis parameters, which enables targeted control of their physical properties. The obtained data are discussed.     

Theoretical model for describing degradation of thin hydrogen-containing films

A new theoretical model is proposed to describe the behavior of films of composite hydrogen-containing compounds during heat treatment. The model is based on the thermal generation of hydrogen atoms and atoms of the composite compounds with their subsequent diffusion to the boundaries of the film and percolation through the surface into the atmosphere. Calculations are performed for the heat treatment of films of silicon nitride. A comparison with the experimental data in the literature demonstrates the high efficiency of the proposed model. Zh. Tekh. Fiz. 67, 105–110 (August 1997)     

Thermodynamic Analysis of the Behavior of Trimethyl Borate as a Precursor for Chemical Vapor Deposition of Boron-Containing Films

The chemical vapor deposition (CVD) of boron-containing films involving the trimethyl borate precursor has been modeled in the ranges of pressures 0.03 ≤ Р, Torr ≤ 760 and temperatures 300 ≤ Т, K ≤ 2000. The CVD diagram of this system was found to feature existence fields of the following phase complexes: В + В₄С, В4С + В₂О₃, С + В₂О₃ + В₄С, С + В₂О₃, С + В₂О₃ + НВО₂, С + НВО₂, С + В₄С, and a В₄С phase.     

Chemical and physical properties in layers and interfaces of nanolayered Si(100)/Ni/BCxNy stacks

Layered stacks of the structure Si(100)/Ni/BC_xN_y were produced by physical (Ni) and chemical (BCN) vapor deposition. The BCN layers were deposited at temperatures of 200, 300, 400, and 500 °C. The resulting samples were characterized by ellipsometry, X‐ray photoelectron spectrometry, secondary ion mass spectrometry, atomic force microscopy, and X‐ray reflectometry. The formed structures of the samples synthesized at 200 and 500 °C, respectively, were determined. For the synthesis temperature of 200 °C, compounds with Ni–C bonds were found at the interface Ni/BC_xN_y. For the sample produced at 500 °C, compounds with Ni–Si bonds were identified, dispersed as particles or droplets in the corresponding interface. Copyright © 2015 John Wiley & Sons, Ltd.     

Structural and mechanical properties of KН2PО4 single crystals with embedded nanoparticles and organic molecules

Single crystals of KDP crystals with embedded Urea molecules and TiO₂ nanoparticles have been grown from aqueous solution by the temperature lowering method. The effect of the organic molecules and nanoparticles on the structural and mechanical properties has been studied. It has been observed that addition of Urea molecules improves laser induced damage threshold and mechanical strength of the crystal, while TiO₂ nanoparticles have the opposite effect. The structure and composition of KDP:Urea crystal are studied by three‐crystal X‐ray diffraction analysis, which reveals the existence of a correlation between the increase of the microhardness value and the change of the crystal lattice parameter. The surface features of KDP:TiO₂ crystals are analyzed by scanning electron microscopy that reveals the presence of quasi‐equidistant growth bands caused by capture of the nanoparticles. It is shown that the rise of TiO₂ nanoparticles concentration up to 10⁻⁴ wt.% and higher resulted in 3‐fold reduction of the laser damage threshold of KDP:TiO₂ relative to pure KDP in [001] and [100] crystallographic directions. It is found that microhardness and fracture toughness decrease at the nanoparticles concentration of 10⁻³ wt.% due to crack formation at crystal lattice discontinuities. The grown crystals also have been subjected to dielectric studies.