N. I. Fainer

Growth of PbS and CdS thin films by low-pressure chemical vapour deposition using dithiocarbamates

Abstract Thin films of cadmium and lead sulphides grown by chemical vapour deposition (CVD) and remote plasma enhanced chemical vapour deposition (RPECVD) using dithiocarbamates as precursors were prepared on fused silica, sapphire, (111)Si and (111)InP substrates. These films were deposited in the temperature range 473–873 K. It was established that the activation energy of the CVD process is 191.5±1.5 kJ mol −1 . The structure of polycrystalline films was halenide for PbS and wurtzite for CdS. It was also found that r.f.-plasma activation of the gas phase decreases remarkably the growth temperature and orders the film structure. RPECVD sulphide films had a high degree of preferred orientation.

Synthesis of nanocrystalline silicon carbonitride films by remote plasma enhanced chemical vapor deposition using the mixture of hexamethyldisilazane with helium and ammonia

Abstract The silicon carbonitride films were synthesised by remote plasma enhanced chemical vapor deposition (RPECVD) using a mixture of ammonia, helium and hexamethyldisilazane Si2NH(CH3)6 as the volatile single-source precursor. Different analysis techniques such as IR, Raman spectroscopy, ellipsometry, X-ray photoelectron spectroscopy, EDS, scanning electron microscopy, high-resolution electron microscopy, selective area electron diffraction and X-ray diffraction using synchrotron radiation were used to study their physical and chemical properties. The formation of chemical bonding was shown to occur between Si, C, N atoms in the ternary compound. The chemical composition of these films depended mainly on the ammonia concentration in the gaseous phase. It was established that there is a distribution of nanocrystals in the amorphous matrix in these films.

Use of hexamethylcyclotrisilazane for preparation of transparent films of complex compositions

This paper reports on the results of the thermodynamic modeling of chemical vapor deposition of SiCxNy silicon carbonitride films with the use of the volatile organosilicon compound hexamethylcyclotrisilazane (HMCTS) over a wide temperature range 300–1300 K at low pressures of 10−2−10 Torr. It is demonstrated that there are ranges of conditions under which the gas phase is in equilibrium with a mixture of solid phases SiC + Si3N4 + C with the total composition represented in the form of the ternary compound SiCxNy. Transparent silicon carbonitride films of different compositions are experimentally obtained under conditions in the above range through plasma-enhanced chemical vapor deposition at a pressure of 5 × 10−2 Torr and temperatures of 373–1023 K with the use of the initial gaseous mixture of hexamethylcyclotrisilazane and helium. The chemical and phase compositions of the films are determined and their properties are investigated using ellipsometry, IR and Raman spectroscopy, spectrophotometry, energy-dispersive spectroscopy, and synchrotron X-ray powder diffraction. It is shown that the films synthesized at low temperatures of 373–573 K contain a considerable amount of hydrogen. The results obtained ftom atomic-force and scanning electron microscopy indicate that the films involve nanograins.

The investigation of properties of silicon nitride films obtained by RPECVD from hexamethyldisilazane

Abstract The silicon nitride films were obtained by remote plasma enhance chemical vapor deposition (RPECVD) using hexamethyldisilazane or its mixture with ammonia in the range 373–773 K. The correlations between the chemical composition, deposition rates, optical, electrical and structural properties and the growth conditions were established. It was found that the formation of two polycrystalline hexagonal phases SiC and Si3N4 was realized by using pure hexamethyldisilazane as precursor. The ammonia addition in gas mixture leaded to change of the chemical composition and structure of silicon nitride films, namely, the disappearance of carbon-bonding and SiC formation, and the order of hexagonal silicon nitride.

Chemical stability of hydrogen-containing boron nitride films obtained by plasma enhanced chemical vapour deposition

The purpose of this paper is the investigation of the dehydrogenation kinetics of boron nitride films during thermal annealing. BNx:H films on silicon substrates were prepared by remote plasma enhanced chemical vapour deposition at 473 K using a mixture of borazine and helium. IR spectroscopy and ellipsometry were used to characterize the film properties and composition. The films contain a certain amount of hydrogen in BH and NH bonds. The breakage kinetics of these bonds is different. The breakage of NH bonds determines the hydrogen annealing kinetics at 973–1073 K. The low-temperature annealing (673–873 K) of BH bonds is sensitive to the generation of hydrogen from NH bonds. Heat treatment leads to ordering of the films.

Chemical Composition of Boron Carbonitride Films Grown by Plasma-Enhanced Chemical Vapor Deposition from Trimethylamineborane

Boron carbonitride and boron nitride films were grown by plasma-enhanced chemical vapor deposition using trimethylamineborane and its mixtures with ammonia, hydrogen, or helium. The effects of the starting-mixture composition and substrate temperature on the chemical composition of the deposits was studied by ellipsometry, scanning microscopy, IR spectroscopy, Raman scattering, and x-ray photoelectron spectroscopy. The results indicate that the initial composition of the gas mixture, the nature of the activation gas, and substrate temperature play a key role in determining the deposition kinetics and the physicochemical properties of the deposits. Depending on these process parameters, one can obtain h-BN, h-BN + B4C, or BCxNy films.

Synthesis of silicon carbonitride dielectric films with improved optical and mechanical properties from tetramethyldisilazane

Films of silicon carbonitride have been obtained by the plasma chemical decomposition of a gaseous mixture of helium and a volatile organic silicon compound 1,1,3,3-tetramethyldisilazane (TMDS) in the temperature range of 373–973 K. The modeling of the processes of deposition from a gaseous mixture (TMDS + He) in the temperature range of 300–1300 K and pressures of Ptotal0 = 10−2–10 Torr has shown that it is possible to vary the equilibrium composition of the condensed phase depending on the synthesis temperature and the initial gaseous mixture composition. The chemical and phase compositions, as well as physicochemical and functional properties, of the films obtained in the range of 373–973 K have been studied using a complex of modern techniques, including Fourier transformed infrared (FTIR) Raman, X-ray photoelectron (XPS) and energy-dispersive spectroscopy (EDS), scanning electron (SEM) and atomic-force microscopy (AFM), X-ray diffraction using synchrotron radiation (XRD-SR), ellipsometry, and spectrophotometry. The electrophysical parameters are determined using the C-V and I-V characteristics, and the microhardness and Young’s modulus are determined by the nanoindentation method. It is established that the chemical composition of low-temperature (373–673 K) films of silicon carbonitride corresponds to a gross formula of SiCxNyOz: H, while that of high-temperature films corresponds to SiCxNy. The presence of nanocrystals with the phase composition close to the standard phase α-Si3N4 is detected in the films. It is shown that all of the films are perfect dielectrics (k = 3.8–6.4, ρ = 2.2 × 1010−1.3 × 1011 Ohm · cm), possess high transparency (∼98%) in a wide spectral range of 280–2500 nm, and have a high microhardness (3.8–36 GPa) and Young’s momentum (125–190 GPa).

Tris(diethylamino)silane—A New Precursor Compound for Obtaining Layers of Silicon Carbonitride

Silicon carbonitride layers have been obtained by chemical deposition from the gas phase with thermal (LPCVD) and plasma (PECVD) activation of the gas mixture of helium with the new volatile siliconorganic compound tris(diethylamino)silane (Et2N)3SiH (TDEAS) in the temperature region 373–1173 K. Thermodynamic simulation of the deposition processes from the gas mixture (TDEAS + He) in the temperature interval 300–1300 K and pressure interval Ptot0 from 1 × 10−2 to 10 mm Hg has revealed the possibility of varying the equilibrium composition of the condensed phase depending on the synthesis temperature and the composition of the initial gas mixture. Physicochemical and functional properties of obtained layers were studied by complex of modern methods. It has been established that the chemical composition of the silicon carbonitride layers obtained by the PECVD method, depending on the deposition conditions, approaches that of silicon oxynitride or nitride, and the composition of those obtained by the LPCVD method approaches that of silicon carbide. The presence of nanocrystals with a phase composition close to the standard α-Si3N4 phase and of carbon inclusions has been found in the layers.

Plasma enhanced chemical deposition of nanocrystalline silicon carbonitride films from trimethyl(phenylamino)silane

Synthetic process for nanocrystalline silicon carbonitride films was developed using plasma-chemical decomposition of a new organosilicon reagent, namely, trimethyl(phenylamino)silane Me3SiNHPh. Synthesis was carried out from the gaseous mixtures, such as Me3SiNHPh + He, Me3SiNHPh + N2, and Me3SiNHPh + NH3, in a reactor in the wide temperature range (473–973 K) under the low pressure (4–5 × 10−2 Torr). Polished wafers of Si(100), Ge(111), and silica glass were used as substrates. Dependences of the chemical and phase compositions, the surface morphology, and the silicon carbonitride optical properties on the process temperature were studied using FTIR and Raman spectroscopy, energy dispersive spectroscopy (EDS), atomic force microscopy (AFM), scanning electron microscopy (SEM), ellipsometry, and spectrophotometry.

Phase composition of thin silicon carbonitride films obtained by plazma endanced chemical vapour deposition using organosilicon compounds

High-temperature silicon carbonitride films are synthesized by plasma decomposition of gas mixtures of 1,1,1,3,3,3-hexamethyldisilazane (HMDS) (the synonym used by IUPAC bis(trimethylsilyl) amine) with ammonia or helium in the temperature range of 673–1273 K. It is shown that silicon carbonitride films, obtained in high temperature processes of the plasma decomposition of organosilicon compounds, are nanocomposite. In their amorphous matrix the crystals belonging to the phases of the α-Si3−nCnN4 family and impurity graphite are embedded. To clarify the previously obtained data by means of the X-ray diffractometry using synchrotron radiation, they are compared with the published results of modeling the structure of these phases. It is shown that nanocrystals belonging to the phases of α-Si3N4, α-Si2CN4, α-SiC2N4, and α-C3N4 are present in the films. An increase in the ammonia concentration in the initial gas mixture causes a decrease in the film hardness from 24 GPa to 16 GPa due to the increased content of α-Si3N4 and α-Si2CN4 nanocrystals having a lower hardness compared to α-C3N4 and α-SiC2N4.