BCN Thin Films Research Articles

Chemical Vapor Deposition of Highly Conjugated, Transparent Boron Carbon Nitride Thin Films.

Ternary materials made up only from the lightweight elements boron, carbon, and nitrogen are very attractive due to their tunable properties that can be obtained by changing the relative elemental composition. However, most of the times, the synthesis requires to use up to three different precursor and very high temperatures for the synthesis. Moreover, the low reciprocal solubility of boron nitride and graphene often leads to BN‐C composite materials due to phase segregation. Herein, an innovative method is presented to prepare BCN thin films by chemical vapor deposition from a single source precursor, melamine diborate. The deposition occurs homogenously at relatively low temperatures generating very high degree of sp2 conjugation. The as‐prepared thin films possess high transparency and refractive index values in the visible range that are of interest for reflective mirrors and lenses. Furthermore, they are wide‐bandgap semiconductor with very positive valence band, making these materials very stable against oxidation of interest as protective coating and charge transport layer for solar cells. The simple chemical vapor deposition method that relies on commonly available and low‐hazard precursor can open the way for application of BCN thin films in optics, optoelectronics, and beyond.

Combining Thermal Spraying and Magnetron Sputtering for the Development of Ni/Ni-20Cr Thin Film Thermocouples for Plastic Flat Film Extrusion Processes

In the digitalization of production, temperature determination is playing an increasingly important role. Thermal spraying and magnetron sputtering were combined for the development of Ni/Ni-20Cr thin film thermocouples for plastic flat film extrusion processes. On the thermally sprayed insulation layer, AlN and BCN thin films were deposited and analyzed regarding their structural properties and the interaction between the plastic melt and the surfaces using Ball-on-Disc experiments and High-Pressure Capillary Rheometer. A modular tool, containing the deposited Ni/Ni-20Cr thin film thermocouple, was developed and analyzed in a real flat film extrusion process. When calibrating the thin film thermocouple, an accurate temperature determination of the flowing melt was achieved. Industrial type K sensors were used as reference. In addition, PP foils were produced without affecting the surface quality by using thin film thermocouples.

XPS and FTIR Studies of Dual Target Sputtered Bcn Thin Films

The ever increasing advancements in semiconductor technology and continuous scaling of CMOS devices mandate the need for new dielectric materials with low-k values. The interconnect delay can be reduced not only by the resistance of the conductor but also by decreasing the capacitance of dielectric layer. Also cross-talk is a major issue faced by semiconductor industry due to high value of k of the inter-dielectric layer (IDL) in a multilevel wiring scheme in Si ultra large scale integrated circuit (ULSI) devices. Recently it has been found that Boron Nitride (BN) films can achieve low-k values around and hardness comparable to diamond [1][2]. BN is hygroscopic in nature. In this respect carbon can be added to the BN structure to produce Boron Carbon Nitride (BCN) films as the possible substitute for BN. The minimum dielectric constant achieved by plasma assisted chemical vapor deposition for a BCN thin film was reported to be 1.9. [2] The BCN films are also instrumental in suppressing the Cu migration [3]. The Young’s modulus of BCN films are reported well above 20 GPa making it one of the suitable options for low-k materials [4]. In the present work, BCN films were deposited by dual target sputtering of boron carbide (BC) target (DC), boron nitride (BN) target (RF) in nitrogen ambient with argon. The films were deposited under various N­2/Ar gas flow ratios and temperature. XPS and FTIR measurements were performed to find the relative chemical compositions, chemical bonds and behavior of the deposited films with respect to change in N­2/Ar gas flow ratios and deposition temperature. REFERENCES [1] Jun Liu, Kian Ping Loh, Ming Lin, Yong Lim Foo, Wei De Wang, and Dong Zhi Ch, Journal of Applied Physics, 96 (2004) 6679. [2] Riedel R., Advanced Materials, 4 (1992) 759. [3] M. K Mazumder, R. Moriyama, D. Watanabe, C. Kimura, H. Aoki, and T. Sugino: Jpn. J. Appl. Phys. 46 (2007) 2006. [4] C. Morant, D. Caceres, J. M. Sanz, and E. Elizalde: Diamond Relat. Mater. 16 (2007) 1441.

Optical Studies of Reactively Co-Sputtered Bcn Thin Films

The motivation behind the boron carbon nitride (BCN) ternary compounds is their similarities in the structure and difference in properties between graphite and hexagonal boron nitride (h-BN). Both theoretical calculations and experimental studies show that BCN compounds exhibit excellent mechanical, optical and electrical properties [1], [2]. In particular, the possibility to control the band gap (EG ) by atomic composition and structure makes them good candidates for the application in electronic and photonic devices [3], [4].The optical characteristic like transmittance is improved with initial incorporation of nitrogen into the film composition and has a stable trend with further increase in nitrogen concentration. Also the optical band gap of BCN (2.2eV-3eV) increased with incorporation of nitrogen and said to follow a linear trend between B4C (2eV) and BN (4eV) [5]. The co-sputtering helps in creation of films with graded indexes of refraction as well. It gives more freedom to vary the composition as when compared to single target sputtering. Thickness uniformity and the film quality are better when using co-sputtering.Dual target approach will be conducted to prepare BCN tin films. In this work we are depositing BCN thin films on quartz substrates using two targets namely B4C and BN using RF power and DC power respectively at different N2/Ar gas flow ratios. Also the input power for B4C and BN are varied to achieve different composition of the BCN thin films to control the optical properties. The optical properties like transmission and reflectance are studied using the UV-visible spectrophotometer. The optical absorption is studied by Tauc plot which is instrumental in finding the optical band gap of the material and the refractive index.REFERENCES[1] I. Caretti, J.M. Albella, I. Jiménez, Diamond Relat. Mater., 16 (2007), p. 1445[2] A. Perrone, A.P. Caricato, A. Luches, M. Dinescu, C. Ghica, V. Sandu, A.Andrei , Appl. Surf. Sci., 133 (1998), p. 239 [3] M.O. Watanabe, S. Itoh, K. Mizushima, T. Sasaki, J. Appl. Phys., 78 (1995), p. 2880 [4] P.R. Fitzpatrick, J.G. Ekerdt, J. Vac, Sci. Technol. A, 26 (2008), p. 1397[5] Optical characterization of BCN films deposited at various N2/Ar gas flow ratios by RF magnetron sputtering.

Hardness Studies of RF Sputtered Deposited Bcn Thin Films

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A functionally graded multilayer approach to the synthesis of boron containing ceramic thin films

Despite their excellent properties, adhesion problems are common for B4C and BCN thin films on different substrates when the film thickness exceeds about 500 nm. Three functionally graded multilayer designs; surface boronizing of the steel substrate before deposition (Boride underlayer/B4C), Ti/TiC/B4C and Ti/TiN/BCN structures were discussed in this study, to alleviate the adhesion problems. Cross-sectional FE–SEM examinations and elemental depth profiling by SIMS revealed the graded structure of the films. The elemental film composition measured by EPMA and the mechanical properties determined by nanoindentation demonstrated the graded chemical composition and the transition of the hardness and Young's modulus values between different layers respectively. The results demonstrated the possibility of growing well adherent boron containing ceramic coatings with thicknesses in the μm range by means of different graded underlayer designs.

Effect of Substrate Heating on the Optical Properties and Chemical Composition of Sputter Deposited BCN Thin Films

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Effect of Substrate Temperature on Optical Properties of BCN Thin Films

Effect of Substrate Temperature on Optical Properties of BCN Thin Films

Comparative corrosion study of binary oxide and nitride overcoats using in-situ fluid-cell AFM

In-situ fluid-cell AFM has been used to investigate the corrosion mechanisms of TaZrO and BCN thin films as protective coatings for magnetic media. This technique allows for real-time, in-situ monitoring of corrosion with nanometer resolution. The technique proved valuable in revealing peculiarities that cannot be detected using conventional techniques. In contrast to the nitride films, the results point to defect-based diffusion type corrosion mechanism in the oxide films.

Influence of assisted ion energy on surface roughness and mechanical properties of boron carbon nitride films synthesized by DIBSD

The BCN thin films were produced by dual ion beam sputtering deposition (DIBSD). The influence of assisted ion energy on surface roughness and mechanical properties of BCN films were investigated. The surface roughness was determined by atomic force microscopy (AFM) and the mechanical properties of BCN firms were evaluated by nano-indentation in N 2 gas. The composition, structure and chemical bonding of the BCN thin films were analyzed by using energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), laser Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). These films appeared as amorphous structure. As a result, the BCN films with the smoothest surface ( R a = 0.35 nm and R p–v = 4.4 nm) and the highest nano-hardness of 30.1 GPa and elastic modulus of 232.6 GPa were obtained at 200 eV and 12 mA with N 2:Ar = 1:1, and the chemical composition of this BCN film was 81 at.% B, 14 at.% C and 5 at.% N. Moreover, several bonding states such as B–N, B–C and C–N were observed in BCN thin films.

Investigation of Reactively Sputtered BCN Thin Films

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Synthesis of BCN thin films by nitrogen ion beam assisted pulsed laser deposition from a B 4C target

Using sintered B 4C as target material, ternary BCN thin films were synthesized on Si(100) substrates by means of reactive pulsed laser deposition assisted by nitrogen ion beam. The composition, bonding configuration and crystalline structure of the synthesized films were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and transmission electron microscopy. The prepared films contain several bonds including B–C, N–C, B–N with B–C–N atomic hybridization. The ablation of the B 4C target results in the deposition of a film with B:C ratio about 3:1, deficient in boron compared with the target material. Nitrogen provided by the ion beam is incorporated in the film and bonded to boron and carbon. Heating of the substrate enhances the incorporation of nitrogen and influences the bonding configuration and crystalline structure of the film as well.

Fullerene-like BCN thin films: a computational and experimental study

Fullerene-like BCN thin films: a computational and experimental study

Corrosion behavior of boron-carbon-nitride films grown by magnetron sputtering

The corrosion behavior of BCN thin films in aqueous solution was investigated. BCN films with different composition were deposited on a platinum plate by magnetron sputtering in the thickness range of 150–280 nm. In order to understand effect of pH of solutions, BC 2.4N samples were immersed in 1 M HCl, 1 M NaCl and 1 M NaOH solution at 298 K, respectively. BCN samples with different carbon content were immersed in 1 M NaOH solutions to investigate the effect of chemical composition on corrosion resistance. The corrosion rate of the samples were measured by ellipsometry. The corrosion rates of B 1.0C 2.4N 1.0 films in the immersion test were NaOH>NaCl>HCl in sequence. With increasing carbon content in BCN films, the corrosion resistance of BCN films is enhanced. The lowest corrosion rate was obtained for B 1.0C (3.2–4.4)N 1.2 films.

Plasma assisted deposition of nanocrystalline BCN thin films and property characterization

Electron-cyclotron-wave-resonance plasma assisted deposition is an effective technique for preparing superhard materials. In this work, nanocrystalline BCN thin films were grown on Si(001) wafers and Corning glass substrates, where the growing surface was bombarded with nitrogen plasma at energies between 60 and 180 eV. Energy-dispersive x-ray analysis revealed the formation of very clean, homogeneous films with a bulk composition around B42C33N25, which changes only slightly with ion energy. Under an atomic force microscope the films displayed a morphology composed of crystallites of about 200 nm in lateral size in cubic habits. Both the x-ray photoelectron spectroscopy and infrared absorption indicated that the deposits are ternary BCN compounds. The films are highly transparent and hard; the Vicker’s hardness scatters in the range of 26–28 GPa. Strong photoluminescence peaked at 430 nm was detected on the as-deposited specimens at room temperature. The band gap for the deposits was estimated to be circ...

Micromechanical and microtribological properties of BCN thin films near the B 4C composition deposited by r.f. magnetron sputtering

Ternary materials with compositions in the B–C–N system offer properties of great interest. In particular, mechanical and tribological properties are expected to be excellent, as they can combine some of the specific properties of BN, B 4C and C 3N 4. In this paper, BCN thin films deposited by r.f. magnetron sputtering are characterized by their micromechanical and microtribological behavior. BCN coatings with different composition were obtained by varying the N 2/Ar proportion in the sputtering gas. Hardness and elastic modulus of the coatings were measured by nanoindentation. The adhesion and friction coefficient against diamond have been evaluated by microscratch and the coatings have been characterized in their wear behavior at the nanometric scale. These mechanical and tribological properties have been related to film composition and structure, which have been studied in a previous work. It is found that the measured wear resistance at the nanometric scale is directly related to the coating microhardness rather than friction behavior or adhesion of the coating to the substrate, which are the determinant factors in the macroscopic scale wear behavior.

BCN thin films near the B 4 C composition deposited by radio frequency magnetron sputtering

Abstract Materials with composition within the system B–C–N are very interesting because they are expected to combine some of the excellent properties of BN, B4C and C3N4. In this work our interest is focused on the region around B4C in the B–C–N composition diagram. Films were deposited by radio frequency magnetron sputtering using a target of sintered B4C. A mixture of Ar and N2 was used as the plasma gas at a constant working pressure of 2×10−3 mbar, and with variable N2/Ar composition. The substrate was heated to 500°C. Film composition, structure, and mechanical properties are presented. As the N2/Ar content in the plasma gas is varied from 0 to 10%, both secondary ion mass spectroscopy and X-ray photoelectron spectroscopy analyses show a continuous increase in the nitrogen incorporated into the film. From the Fourier transform IR spectra, a structure evolution from B4C towards h-BN can be deduced. Film growth rate increased from 0.5 μm/h to 1 μm/h, whereas film stress decreased from 5 GPa to 2 GPa, and film hardness also decreased from 26 GPa to 12 GPa. From these results, a suitable value of the N2/Ar plasma gas composition can be selected in order to deposit films with a satisfactory low stress while keeping a sufficiently high hardness, as required in hard coating applications.

Phase separation in magnetron sputtered superhard BCN thin films

Abstract The similar crystalline structure of diamond and cubic boron nitride suggests the synthesis of superhard thin films containing boron, carbon and nitrogen. BCN thin films have been prepared by reactive r.f.-magnetron sputtering of a hexagonal boron nitride target in an argon/acetylene atmosphere of a constant pressure of 2 × 10−2 mbar. A deposition temperature of 600 °C leads to nearly hydrogen-free BCN films. At a flow ratio of 0.05% C2H2/Ar, the composition of the deposited BCN films is close to B5CN3 as a result of energy dispersive X-ray (EDX) and elastic recoil detection (ERD) measurements. By applying a r.f.-substrate bias, the ion energy has been varied at a constant ratio of ions to film-forming particles of 4. The BCN films show a maximum in stress at an ion energy of 110 eV due to knock-on subplantation of argon ions and a phase separation into carbon, boron and cubic boron nitride regions as a result of X-ray diffraction investigations. Auger electron- and infra-red spectroscopy.