Carbonitride Thin Films Research Articles

TiCN thin films grown by reactive crossed beam pulsed laser deposition

In this work, we used a crossed plasma configuration where the ablation of two different targets in a reactive atmosphere was performed to prepare nanocrystalline thin films of ternary compounds. In order to assess this alternative deposition configuration, titanium carbonitride (TiCN) thin films were deposited. Two crossed plasmas were produced by simultaneously ablating titanium and graphite targets in an Ar/N2 atmosphere. Films were deposited at room temperature onto Si (100) and AISI 4140 steel substrates whilst keeping the ablation conditions of the Ti target constant. By varying the laser fluence on the carbon target it was possible to study the effect of the carbon plasma on the characteristics of the deposited TiCN films. The structure and composition of the films were analyzed by X-ray Diffraction, Raman Spectroscopy and non-Rutherford Backscattering Spectroscopy. The hardness and elastic modulus of the films was also measured by nanoindentation. In general, the experimental results showed that the TiCN thin films were highly oriented in the (111) crystallographic direction with crystallite sizes as small as 6.0 nm. It was found that the hardness increased as the laser fluence was increased, reaching a maximum value of about 33 GPa and an elastic modulus of 244 GPa. With the proposed configuration, the carbon content could be easily varied from 42 to 5 at.% by changing the laser fluence on the carbon target.

A-SiCxNy thin films deposited by a microwave plasma assisted CVD process using a CH4/N2/Ar/HMDSN mixture: Methane rate effect

Amorphous silicon carbonitride thin films were deposited using a microwave plasma assisted chemical vapour deposition process fed with a mixture of methane, nitrogen, argon and hexamethyldisilazane (Si2C6H19N). Effects of the methane rate on thin films composition, nanostructuration and characteristics are investigated by means of various techniques such as X-ray Photoelectron Spectroscopy, Fourier Transform Infrared Spectroscopy, Transmission Electron Microscopy and UV-Visible absorption. The raise of the methane rate results in less organic, denser films and in an increase of refractive index.

Raman studies on nanocomposite silicon carbonitride thin film deposited by r.f. magnetron sputtering at different substrate temperatures

AbstractRaman studies of nanocomposite SiCN thin film by sputtering showed that with increase of substrate temperature from room temperature to 500 °C, a transition from mostly sp2 graphitic phase to sp3 carbon took place, which was observed from the variation of ID/IG ratio and the peak shifts. This process resulted in the growth of C3N4 and Si3N4 crystallites in the amorphous matrix, which led to increase in hardness (H) and modulus (E) obtained through nanoindentation. However, at a higher temperature of 600 °C, again an increase of sp2 C concentration in the film was observed but the H and E values showed a decrease due to increased growth of the graphitic carbon phase. The whole process got reflected in a modified four‐stage Ferrari–Robertson model of Raman spectroscopy. Copyright © 2010 John Wiley & Sons, Ltd.

Properties of Plasma-Enhanced Atomic Layer Deposition-Grown Tantalum Carbonitride Thin Films

Tantalum carbonitride thin films were deposited by plasma-enhanced atomic layer deposition using the metallorganic precursor tert-butylimido tris (diethylamido) tantalum and hydrogen/argon direct plasma with 600 W radio frequency power. Within the atomic layer deposition temperature window, which ranges from below 200 to , films grow with . At a substrate temperature of , the process yields films with an oxygen impurity content of below 5 atom %. These films have a cubic nanocrystalline structure, a high density of , as well as an excellent low resistivity of . Furthermore, the films show copper diffusion barrier performance comparable to stoichiometric physical vapor deposition TaN and a feasible wetting on multiwall carbon nanotubes. The interface between the tantalum carbonitride film and the silicon substrate was investigated using analytical electron microscopy and shows nitrogen and carbon agglomeration.

Carbonitriding of silicon using plasma focus device

Carbonitride thin films have been deposited on silicon substrate by the irradiation of energetic nitrogen ions emanated from dense plasma focus device. The carbon ions are ablated by the irradiation of relativistic electrons from the insert material (graphite) placed at the anode tip. The x-ray diffraction analysis demonstrates that a polycrystalline thin film consisting of various compounds such as Si3N4, SiC, and C3N4 is formed on the silicon (100) substrate. Crystallinity of different compounds decreases with the increase in angular positions (0°, 10°, and 20°). Raman spectroscopy shows the appearance of graphitic and disordered bands with silicon nitride and silicon carbide indicating the formation of carbonitride. Raman spectra also indicate that broadening of bands increases with the increase in focus deposition shots, leading to the amorphization of the thin film. The amorphization of the thin films depends on the ion energy flux as well as on the sample angular position. The scanning electron microscopy exhibits the damaging of the substrate surface at 0° angular position. The microstructure shows the tubular shape for higher ion dose (40 focus shots). At 10° angular position, a two phase phenomenon is observed with the ordered phase in the solid solution. A smooth and uniform surface morphology showing a small cluster is observed for the 20° angular position.

Composition and mechanical properties of AlC, AlN and AlCN thin films obtained by r.f. magnetron sputtering

Aluminum carbide (Al–C), aluminum nitride (Al–N), and aluminum carbonitride (Al–C–N) thin films were grown onto Si [100] substrates by r.f. reactive magnetron sputtering at 400 °C. The Al–N coatings were obtained by sputtering of Al (99.9%) target in Ar/N 2 atmosphere and the Al–C and Al–C–N by co-sputtering of a binary (50% Al, 50% C) target in argon and in Ar/N 2 mixture, respectively. The d.c. bias voltage was varied between 0 and − 150 V. The films were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), Fourier transformed infrared spectroscopy (FTIR) and the mechanical properties by nanoindentation. The structure of the films has been determined by XRD, which shows that amorphous films are formed in all cases. The variation of polarization bias voltage produced chemical differences in the films. As the bias voltage is increased, the Al content is reduced in all three materials. The nitrogen content also varied between 10 and 14 at.% for Al–N coatings, remaining practically constant (21 at.%) for the Al–C–N films. The Berkovich hardness results were 7.0, 17.2 and 9.2 GPa for Al–C, Al–N, and Al–C–N films, respectively.

Characteristics of Tantalum Carbo-nitride Thin Films Deposited with Atomic Layer Deposition Process

Tantalum carbo-nitride (TaCN) thin films were deposited on SiO2 surface with the plasma enhanced atomic layer deposition (PEALD) and thermal atomic layer deposition using tert-butylimido-tris (diethylamido)-tantalum (TBTDET) and reactive gas such as hydrogen and ammonia. It was confirmed that the film was a mixture of TaC, TaN, Ta3N5 and Ta2O5 with oxide phase formed from the post-deposition uptake of oxygen from the air. It was shown that electrical properties of TaCN film were affected by the phase composition in the film. Effect of the process parameters such as deposition temperature and plasma power was studied and their effect on phase composition and electronic properties was evaluated. The uptake of oxygen after deposition was about 10 atomic % with the PEALD process and about 30 atomic % with thermal ALD process and it is believed that denser film could be obtained with plasma.

Characteristics of Tantalum Carbo-nitride Thin Films Deposited with Atomic Layer Deposition Process

not Available.

Phase Formation in the Tantalum Carbonitride Film Deposited with Atomic Layer Deposition Using Ammonia

Tantalum carbonitride (TaCN) thin films were deposited on surface with plasma enhanced atomic layer deposition (PEALD) and thermal atomic layer deposition using tert-butylimido[tri-diethylamido]tantalum (TBTDET) and ammonia. It was confirmed that the film was a mixture of TaC, TaN, , and with oxide phase formed from the postdeposition uptake of oxygen from the air. It was shown that electrical properties of TaCN film were affected by the atomic composition and phase composition in the film. Effect of the process parameters, such as deposition temperature and plasma power on film composition and electronic properties was studied. Formation of carbide phase was suppressed in the TaCN film deposited with ammonia. As the deposition temperature was increased, the carbide phase and TaN phase in the film were increased, phase in the film was decreased and the film resistivity was decreased. The uptake of oxygen after deposition was about 5 atom % with the PEALD process and about 30 atom % with thermal ALD process and it is believed that denser film could be obtained with plasma. The resistivity of TaCN film deposited at and using PEALD process was about .

Characterization of Boron Carbonitride (BCN) Thin Films Deposited by Radiofrequency and Microwave Plasma Enhanced Chemical Vapor Deposition

Boron carbonitride (BCN) thin films with a thickness of ~4 µm were synthesized on Si (100) substrate by radiofrequency and microwave plasma enhanced chemical vapor deposition using trimethylamine borane [(CH3)3N.BH3)] as a molecular precursor. The microstructures of the films were evaluated using field emission scanning electron microscopy (FE-SEM) and X-ray diffractometry (XRD). Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were used to analyze the chemical bonding state and composition of the films. It has been observed that the films were adhered well to the silicon substrate even after being broken mechanically. XRD and FESEM results showed that the films were x-ray amorphous, rough surface with inhomogeneous microstructure. The micro hardness was measured by nano-indentation tester and was found to be approximately 2~7 GPa. FT-IR suggested the formation of the hexagonal boron carbonitride (h-BCN) phase in the films. Broadening of the XPS peaks revealed that B, C and N atoms have different chemical bonds such as B-N, B-C and C-N. The impurity oxygen was detected (13~15 at.%) as B-O and/or N-O.

Structural and optical properties studies of sputtered a-SiCN thin films

Amorphous silicon carbonitride (a-SiCxNy) thin films were deposited by reactive sputtering from SiC target and N2/Ar mixtures. Their structural study was carried out by mean of RBS, FTIR, Raman and electron spin resonance analysis. The optical properties were determined by UV-visible spectroscopy. The fact to introduce different amounts of nitrogen with argon in the gas phase induced structural changes which are visible since 5 % of N2. For more than 30 % of nitrogen in the gas mixture, a N-saturated Si–C–N film were formed. The increase of nitrogen gas concentration induced the appearance of C-C sp2 character, an increase of the C≡N and dangling bonds densities. All these structural variations leaded to an increase of optical band gap from 1.75 to 2.35 eV.

Thin silicon carbonitride films are perspective low- k materials

The multifunctional amorphous and nanocrystalline silicon carbonitride thin films were synthesized by RPECVD using the gas mixture of hexamethyldisilazane (HMDS) with ammonia and helium within temperature range 600–1073 K. IR spectroscopy, Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), ellipsometry, X-ray diffraction using synchrotron radiation (XRD-SR), scanning electron microscopy (SEM), high-resolution electron microscopy (HREM), selected area electron diffraction (SAED), atomic force microscopy (AFM), measurements of hardness by nanoindenter, electrophysical and spectrophotometry measurements were applied to study their physicochemical properties. The presence of chemical bonding among Si, N, and C elements in SiC x N y films was established. According to data of XRD-SR, HREM, and SAED, the formation of the solid substitution solution occurs, with lattice parameters close to those of the standard phase α-Si 3N 4 in which a part of silicon atoms is substituted by carbon atoms. The analysis of electrophysical, optical, and mechanical properties of these films indicates the possibility for applications as low- k materials with mechanical characteristics and transparent layers in wide region of spectra (400–2200 cm −1).

Thin TiCN Films Prepared by Hybrid Magnetron-Laser Deposition

Titanium carbonitride thin films were prepared by hybrid deposition arrangement combining DC magnetron sputtering and KrF pulsed laser deposition. Carbon and titanium species were simultaneously deposited on the same rotated Si substrate. Films were fabricated at room substrate temperature in argon–nitrogen ambient atmosphere, for laser fluence of 15 J · cm−2 and magnetron power of 150 W. Film properties were modified by RF discharge held between the target and substrate. Films were studied by XRD and glow discharge optical emission spectroscopy (GDOES). Mechanical and electronic properties (XPS) were also measured.

Homogeneous Decomposition of Aryl- and Alkylimido Precursors for the Chemical Vapor Deposition of Tungsten Nitride: A Combined Density Functional Theory and Experimental Study

MOCVD growth of tungsten nitride (WN(x)()) and tungsten carbonitride (WN(x)()C(y)()) thin films has been reported from the complexes Cl(4)(CH(3)CN)W(NR) (1: R = Ph; 2: R = (i)Pr; 3: R = C(3)H(5)). To evaluate the role of the imido substituent in film growth, gas-phase homogeneous decomposition of precursor molecules was investigated using density functional theory (DFT) calculations. Computational results and NMR kinetics of acetonitrile exchange by 2 in solution verified that dissociation of the acetonitrile ligand should be facile for 1-3 in the temperature range used for film growth (>450 degrees C). A computational search for transition states for cleavage of W-Cl bonds in the presence of H(2) carrier gas was consistent with a sigma-bond metathesis pathway. Natural bonding orbital (NBO) analysis and bond energy calculations indicated that 1 has a stronger N-C(imido) bond and a slightly weaker W-N bond than 2 and 3, suggesting a greater role for W-N bond cleavage in depositions from 1. These results are consistent with mass spectrometric fragmentation patterns from 1-3 and low nitrogen content in films deposited from 1 as compared to those from 2 and 3.

Hard BC xN y thin films grown by dual ion beam sputtering

Boron carbonitride thin films were deposited by sputtering of a B 4C target with Ar–N 2 ion assistance. BC x N y films were grown onto Si (001) at room temperature. The chemical composition and the type of bonding were determined by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The hardness of the films was measured with a nanoindenter. The chemical analysis of the samples indicates the formation of two different compounds, a ternary BC x N y and a binary carbonitride CN x . All the films showed high hardness, in the range 16–33 GPa, which clearly increases as the BC x N y content in the sample increases. In this study the highest hardness (i.e. 33 GPa) was obtained when the BC x N y content in the sample was 50%. The average composition of this BC x N y was estimated by XPS as 20 at.% carbon and 12 at.% nitrogen.

Structural and optical properties of amorphous hydrogenated silicon carbonitride films produced by PECVD

Amorphous hydrogenated silicon carbonitride thin films (a-Si:C:N:H), deposited by plasma enhanced chemical vapour deposition (PECVD) using hexamethyldisilazane (HMDSN) as monomer and Ar as feed gas, have been investigated for their structural and optical properties as a function of the deposition RF plasma power, in the range of 100–300 W. The films have been analysed by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), UV–vis–NIR spectrophotometry and atomic force microscopy (AFM). From the analysis of the FT-IR spectra it results that the films become more amorphous and inorganic as RF plasma power increases. The incorporation of oxygen in the deposited layers, mainly due to the atmospheric attack, has been evaluated by XPS and FT-IR spectroscopy. Reflectance/transmittance spectra, acquired in the range of 200–2500 nm, allow to descrive the film absorption edge for interband transitions. A relationship between the optical energy band gap, deduced from the absorption coefficient curve, and the deposition RF plasma power has been investigated. The reduction of the optical energy gap from 3.85 to 3.69 eV and the broadening of the optical absorption tail with RF plasma power increasing from 100 to 300 W are ascribed to the growth of structural disorder, while the increase of the refractive index, evaluated at 630 nm, is attributed to a slight densification of the film. The AFM analysis confirms the amorphous character of the films and shows how the deposited layers become rougher when RF plasma power increases. The wettability of the film has been studied and related to the chemical composition and to the morphology of the deposited layers.

Tailored stoichiometries of silicon carbonitride thin films prepared by combined radio frequency magnetron sputtering and ion beam synthesis

Homogenous Si–C–N films of 120 nm thickness have been successfully fabricated by means of rf magnetron sputtering combined with ion implantation. These means are capable of producing various tailored stoichiometries of so far unequaled nitrogen concentration and high purity (O<0.2at.%, H<0.5at.%). The achieved compounds Si2CN4,SiCN2, and SiC2N2.2 consist of SiN4 tetrahedron layers interconnected by carbodiimid bridges. Stoichiometry, chemical binding states, and homogeneity of these layers as well as the reproducibility have been investigated by means of x-ray photoelectron spectroscopy, Fourier transform infrared, non-Rutherford back scattering spectroscopy, and resonant nuclear reaction analyses. Furthermore, sputter induced effects on the Si–C–N system during surface analytical characterization using Ar+ ions at 250 and 3250 eV for sputter cleaning have been studied carefully.

Tungsten Allylimido Complexes Cl4(RCN)W(NC3H5) as Single-Source CVD Precursors for WNxCy Thin Films. Correlation of Precursor Fragmentation to Film Properties

A mixture of the tungsten allylimido complexes Cl(4)(RCN)W(NC(3)H(5)) (3a, R = CH(3) and 3b, R = Ph) was tested as a single-source precursor for growth of tungsten nitride (WN(x)) or carbonitride (WN(x)C(y)) thin films. Films deposited from 3a,b below 550 degrees C contained amorphous beta-WN(x)C(y), while those deposited at higher temperatures were polycrystalline. Film growth rates from 3a,b ranged from 5 to 10 A/min over a temperature range of 450-650 degrees C, and the apparent activation energy for film growth was 0.15 eV. A plot of the E(a) values for deposition from Cl(4)(RCN)W(NR') [R' = Ph, (i)Pr, allyl] against the N-C imido bond strengths for the analogous amines R'NH(2) is linear, implicating cleavage of the N-C bond as the rate-determining step in film growth. The correlation of mass spectral fragmentation patterns for Cl(4)(RCN)W(NR') with film properties such as nitrogen content supports the significance of facile N-C bond cleavage in film growth.

Boron carbide and boron carbonitride thin films as protective coatings in ultra-high density hard disk drives

Boron carbide (B 4C) and boron carbon nitride (B x C y N z ) thin films were synthesized by pulsed DC magnetron sputtering. Effects of target power, target pulse frequency, substrate bias and pulse frequency on surface roughness were studied by AFM over sampling areas of 20 μm × 20 μm. For B 4C, the combination of target power of 75 W/50 kHz and substrate bias of −100 V/2 kHz results in the smallest surface roughness. Compressive stress in these films is around 2.5 GPa. These B 4C films have a hardness of 30 ± 5 GPa and reduced modulus of 250 ± 50 GPa. Nitrogen incorporation into B 4C films, which gives B x C y N z thin films, has a beneficial effect. When deposited under similar conditions with substrate bias pulsed at −100 V / 20 kHz, the root-mean-square surface roughness decreases to 0.19 nm, compared with 0.28 nm for B 4C. The hardness of B x C y N z is 20 ± 3 GPa, and reduced modulus is 210 ± 30 GPa. Auger electron spectroscopy was used to characterize the film composition. High-resolution cross-sectioned TEM images and diffraction show that both films are amorphous. Corrosion studies indicate that B x C y N z is a better protective coating for hard disk substrates than B 4C and CN x films. This is attributed mainly to the smoother morphology of B x C y N z films.

Effect of substrate temperature on the growth of ternary Al–C–N thin films by reactive magnetron sputtering

Oxygen-free aluminum carbonitride thin films were synthesized by reactive magnetron sputtering of Al target with a gas mixture of Ar, CH 4 and N 2. The effect of substrate temperature varying from the room temperature to 400 °C was investigated, since the crystalline Al–C–N compounds can be modeled as the stacking of zigzag building blocks Al 2C 2, Al 2C and AlN. Generally, film growth proceeds preferably along the [0 0 0 l] direction, but m-plane growth makes its competitive presence in the temperature range from 50 to 260 °C, as revealed by X-ray diffraction. For the samples with a typical composition of Al 50C 13N 37, the size of crystallites, and thus the root-mean-square roughness of the film, becomes larger with increasing substrate temperature. Berkovich hardness is over 27.0 GPa for all as-deposited films and a maximum value of 33.6 GPa was measured in the sample prepared at 300 °C. These results indicated that hard Al–C–N coatings with well-controlled orientation can be fabricated by reactive magnetron sputtering at moderate substrate temperatures.