ICMCTF2009 Session B3-2: CVD Coatings and Technologies

Monday, April 27, 2009 1:30 PM in Room Royal Palm 1-3

Monday Afternoon

Time Period MoA Sessions | Abstract Timeline | Topic B Sessions | Time Periods | Topics | ICMCTF2009 Schedule

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1:30 PM B3-2-1 Mechanical Behavior of PECVD Silicon Oxide, Oxynitride and Nitride: A Comparative Micro-Cantilever Deflection Study
K. Matoy (KAI Kompetenzzentrum automobil- und Industrie-Elektronik GmbH, Austria); R. Pippan (Erich Schmid Institute Leoben, Austria); G. Dehm (University of Leoben, Austria); H. Schönherr, T. Detzel (Infineon Technologies AG, Austria)
The mechanical behavior of plasma enhanced chemical vapour deposited (PECVD) silicon oxide, oxynitride and nitride films was investigated. Hardness, Young's modulus, fracture stress and fracture toughness were determined by nanoindentation and the micro-cantilever deflection technique. The micro-cantilever experiments revealed linear elastic behavior of all PECVD materials. Up to failure bending strength of 4.2GPa for silicon oxide, 6.5GPa for silicon oxynitride and 7.9GPa for silicon nitride were observed. The fracture toughness values obtained from the bending experiments scale between 0.7MPam^1/2 and 1.6MPam^1/2 depending on the chemical composition. Furthermore, a correlation between the fracture properties and the refractive index was observed, which may offer the possibility to estimate the mechanical properties by the refractive index.
1:50 PM B3-2-2 Properties and Tribological Behaviour of CVD TiBN-Coated Cutting Tools
D. Stiens (Walter AG, Germany); I. Dreiling (University of Tuebingen, Germany); H. Holzschuh (Walter AG, Germany); T. Chasse (University of Tuebingen, Germany)
CVD Titanium Boronitride coatings show interesting results in cutting tests. To understand the wear behaviour Pin on Disk tribological model tests of the coatings have been performed at ambient and elevated temperature against 100Cr6 steel and Aluminium as counter materials. Coatings with different Boron contents have been studied. The samples from cutting tests and tribological experiments were subsequently investigated by Laser Raman Spectroscopy in order to find products of tribochemical reactions. Different Titanium Oxide Phases which originate from coating oxidation have been detected. Also Iron borate phases which originate from reactions with the friction partner were found. The influence of laser heating has been systematically studied by variation of the Laser power. To estimate the local temperature samples have been tempered at different temperatures in air. The oxidation products induced by tempering were investigated by Raman at low Laser power and compared to those obtained by Laser-induced oxidation.
2:10 PM B3-2-3 Experimental Thermodynamics for the Evaluation of ALD Growth Processes
E. Blanquet, P Violet (SIMAP, Grenoble-INP, CNRS, France); D. Monnier (STMicroelectronics, France); I. Nuta (SIMAP, Grenoble-INP, CNRS, France); C. Chatillon (SIMAP, Grenoble-INP, CNRS)

Atomic Layer Deposition (ALD) is applied in many advanced technologies that require control of film properties in the nanometer or sub-nanometer scale. ALD finds use mainly in semiconductor applications but also in solar energy, catalysis, micro-systems and biological applications. ALD films can be used to improve oxidation resistance, corrosion resistance, to improve electrical or optical properties … Atomic layer deposition (ALD) , which is based on the sequential self-limiting surface reactions from generally two gaseous precursors, provides an ideal technique for depositing ultrathin and conformal films.

To develop and optimize an ALD process for a new material requires knowledge of the reactions mechanisms. Most of the studies on ALD modeling have been dedicated on the two precursors surface reactions. However, the most commonly use of organometallic molecule precursors with the occurrence of thermal decomposition requires an understanding of the gas-p hase chemical reactions. Information on physical and chemical behavior of this kind of precursor is scarce and namely species that were transported to the ALD deposition chamber are generally unknown. Mass spectrometer coupled with a Knudsen effusion cell has already proved to be a powerful tool for studying the stability of gaseous molecules, thermodynamics of condensed phases and, more generally vaporization processes. The identification and quantification of the actual species present in the gaseous phase can be determined using a specific system composed of a Knudsen effusion cell coupled with a mass spectrometer. This presentation describes the application of such approach for TaN and ZrO2 ALD deposition processes.

2:50 PM B3-2-5 Effect of Air Exposure on Cu Diffusion Barrier Properties of TaN Thin Films Grown by Atomic Layer Deposition
O.H. Kim, D.J. Kim, K.C. Kim, H.M. Ajmera, T.J. Anderson, J. Koller, L. McElwee-White, D.P. Norton (University of Florida)
The effect of exposing TaN diffusion barriers to air was studied by characterizing the interfacial reactions of the Cu/TaN/Si stack with and without air exposure as a function of annealing temperature. TaN thin films were grown on Si (100) substrate by atomic layer deposition (ALD) using (Et2N)3Ta=NBut [tert-butylimido tris(dimethylamido) tantalum, TBTDET] and NH3 as precursors. TBTDET exposure time and growth temperature were optimized to give self-limiting adsorption. Cu thin films were subsequently deposited on TaN/Si by chemical vapor deposition (CVD) using (tmvs)CuI(hfac) as a single source precursor. To investigate the effect of exposure of the TaN barrier film to air before deposition of the copper layer in the stacks, the TaN/Si samples were either directly transferred to the Cu-CVD chamber under vacuum or first exposed to room temperature air before loading into the chamber. An interfacial layer of TaOxNy was observ ed between Cu and TaN diffusion barrer in the air exposed samples. As a diffusion barrier test, the Cu/TaN/Si structures were thermally annealed under nitrogen at elevated temperature for 30 min. The barrier quality of 4 nm TaN films was evaluated by observing the breakdown temperature of annealed Cu/TaN/Si stacks using X-ray diffraction, sheet resistivity measurements, and etch-pit tests. Interestingly, it was found that the breakdown temperatures of air exposed films are higher than those vacuum transferred. The TaOxNy interfacial layer appears to have a beneficial role in preventing Cu transport.
3:10 PM B3-2-6 DLI-CVD of M-TiO2 (M = Ag, Cu) Antibacterial Thin Films
J. Mungkalasiri (Cirimat - Cea, France); L. Bedel, F. Emieux (CEA, France); J. Doré, F. Renaud (Nosoco.tec, France); F. Maury (CNRS ENSIACET, France)
M-TiO2 (M = Ag ; Cu) nanocomposite layers were grown by pulsed direct liquid injection chemical vapor deposition (DLI-CVD) on stainless steel with the goal to produce bactericidal surfaces. Liquid solutions of titanium tetra-isopropoxide (TTIP), silver pivalate (AgPiv) and copper tetramethyl heptadionate (Cu(tmhd)2) in appropriate solvents were used as Ti , Ag and Cu molecular sources, respectively. The deposition temperature was typically 683 K and the total pressure was 800 Pa. Monodisperse Ag nanoparticles (5-10 nm) are embedded in an anatase matrix. A bactericidal behavior determined by the JIS Z 2801 standard test was found for Ag-TiO2 films with a silver content lower than 1 at.%. An increase of the Ag content of the films increases the numbers of metal particles rather than their size. By contrast, when Cu is used as antibacterial agent, it is incorporated as metal particles with a large size distribution ranging from 50 to 200 nm depending on the copper content of the films. The influence of the growth conditions on the structural features and the antibacterial properties of the thin films is reported and discussed.
3:30 PM B3-2-7 Evaluation of the Tungsten Diphenylhydrazido Complex Cl4(CH3CN)W(NNPh2) as a Precursor for CVD of WNxCy
D.J. Kim, O.H. Kim, T.J. Anderson, J. Koller, L. McElwee-White, L.C. Leu, D.P. Norton (University of Florida)

The tungsten diphenylhydrazido complex Cl4(CH3CN)W(NNPh2) (1) was used to deposit tungsten carbonitride (WNxCy) by metal-organic chemical vapor deposition (MOCVD) in the temperature range 300 to 700 °C. The effect of deposition temperature on the film microstructure, surface morphology, chemical composition, bonding states, growth rate, electrical resistivity, lattice parameter, and grain size was studied. The microstructure of films deposited using 1 was amorphous below 500°C and polycrystalline above this temperature. Between 500 and 700°C the lattice parameter varied from 4.15 to 4.20 Å, while the average grain size increased from 25 to 55 Å. XPS results for films deposited using 1 indicate that W is primarily bonded to N and C for films deposited over the entire deposition temperature range. The growth rates of films deposited using 1 varied from 1.0 to 25.4 Å/min and showed Arrhenius behavior in the rang e 300 to 450°C with an apparent activation energy of 0.49 eV. The barrier quality of Cu/WNxCy/Si stacks was evaluated using XRD patterns and cross-sectional TEM images along with EDS. The integrity of both Cu/WNxCy and WNxCy/Si interfaces was retained after annealing at 500 °C for 30 min. XRD spectra revealed no Cu3Si peaks and EDS qualitative analysis showed a sharp decrease in the Cu Kα peak at the Cu/WNxCy interface. Hence, WNxCy films deposited at 400°C are viable materials to serve as a Cu diffusion barrier. The properties of films deposited with 1 are compared to those deposited from tungsten piperidylhydrazido complex Cl4(CH3CN)W(N-pip) and tungsten imido complexes Cl4(CH3CN)W(NR) (R = Ph, iPr, and allyl)1 to provide insight into the effect of incorporating hydrazido and imido ligands on film properties.

1 O. J. Bchir, K. M. Green, H. M. Ajmera, E. A. Zapp, T. J. Anderson, B. C. Brooks, L. L. Reitfort, D. H. Powell, K. A. Abboud, L. McElwee-White, J. Am. Chem. Soc. 127 (2005) 7825-7833.

3:50 PM B3-2-8 Silicon Carbide CVD for Polycrystalline Growth: Thermodynamic Evaluation vs. Film Morphology
J. Trevarthen (SIMAP, Grenoble-INP, CNRS, France); A. Claudel, R. Martin (ACERDE, France); G. Chichignoud, M. Morais (SIMAP, Grenoble-INP, CNRS, France); E. Blanquet (SIMAP, Grenoble-INP, CNRS, Framce); M. Pons (SIMAP, Grenoble-INP, CNRS, France)

Polycrystalline silicon carbide (SiC) is widely used in a range of commercial applications due to its resistance to extreme conditions. This resistance is improved by increasing the crystallinity and purity of the silicon carbide.

High temperature Chemical Vapour Deposition as a process allows greater control over a wider range of reaction parameters (temperature, pressure, ratio of injected gaseous precursors) when compared to other techniques such as Physical Vapor Transport. The variation of these parameters allows control over properties of the final material such as its morphology, crystalline quality and composition. As such it is preferable for the growth of pure, highly crystalline SiC.

Thermodynamic calculations have been performed on a CVD system employing H2 and methyltrichlorosilane (MTS) for a temperature range of 1200-1600°C, a pressure range of 150-250 mbar and H2/MTS ratios of 5-150. The corresponding data was u sed to calculate the theoretical supersaturation of the gaseous system at equilibrium and the composition of the solid deposit also at equilibrium, which were correlated to experimental data obtained for the HT-CVD process within these ranges of reaction parameters. Characterization techniques such as FEG-SEM, EBSD, XRD, profilometry were used to evaluate film roughness and film morphology, especially grain size and orientations.

4:10 PM B3-2-9 Adhesion and Homogeneity of a-C:H:Si Films Deposited in a Modified Plasma Nitriding System for Industrial Application
C. Forsich, D. Heim (University of Applied Sciences, Austria); T. Mueller (Rubig GmbH & Co KG Anlagentechnik, Austria)
Si doped diamond-like carbon coatings (a-C:H:Si) have attracted significant attention owing to their desirable properties, e.g. chemical inertness, good corrosion resistance, low friction coefficient and reduced wear. These properties make a-C:H:Si films interesting for industrial application on machine parts and tools. a-C:H:Si deposition on plasma nitrided (with compound layer) and on oxidized steel substrates which were prior nitrided was carried out in a commercial available DC plasma nitriding apparatus in one run. This technique has the potential to upscale the a-C:H:Si process to dimensions up to several meters whereas parameters are used comparable to plasma nitriding, such as pressure, gas flows and temperature. In contrast to PVD (physical vapour deposition) it is not possible to deposit metallic interlayers consisting of Cr and Ti. Coatings with beneficial tribological properties were obtained resulting in a friction coefficient down to 0.05. Rockwell C tests exhibited excellent coating adhesion with pre-treatment prior deposition. However, in some cases scratch tests resulted in critical loads up to 10-15 N. Several interfaces and different gradient films were deposited in order to further improve the adhesion behaviour. The homogeneity of the a-C:H:Si films deposited on complex geometric substrates strongly depends on the pressure and gas mixture used in the process. Therefore, parameter variations were systematically carried out. The process gases H2, Ar, C2H2, CH4 as well as HMDSO (hexamethyldisiloxane) and TMS (tetramethylsilane) were regulated by mass flow controllers and fed into the vacuum chamber. The determination of the composition of the a-C:H:Si films and the interlayers was carried out using GDOES (glow discharge optical emission spectroscopy). The hardness was evaluated by a nano-indenter and the topography of the layers was characterized by means of SEM (scanning electron microscopy) whereas t h e tribological properties were assessed with a ball-on-disc test.
4:30 PM B3-2-11 Molecular Beam Mass Spectrometry and Modelling of CH4-CO2 Plasmas in Relation with Polycrystalline and Nano-Smooth Diamond Deposition
T. Gries, L. Vandenbulcke, S. de Persis, C. Met (ICARE-CNRS, France); O. Aubry (GREMI-Polytech/Université d'Orléans, France); J.L. Delfau (ICARE-CNRS, France)
CH4 - CO2 plasmas have been studied by emission spectroscopy, microwave interferometry, Langmuir probing and molecular beam mass spectrometry (MBMS). MBMS allowed us studying the variations of the concentration of both stable species (H2, CH4, CO, CO2, C2H2, …, C6H6, C8H6) and radicals (H, OH, CH3, C3H3, C3H5, C6H5…) as a function of the inlet composition, total flow rate, power density injected in the plasma and distance from the substrate. The other techniques have been used to deduce the variations of the plasma parameters like the gas kinetic temperature, the electron density and the electron temperature. A modelling of the plasma kinetics is based on a combustion mechanism which incorporates more than 150 species and 850 reactions and a specific dissociation mechanism including about 50 species. The calculation results are obtained from a CRESLAF version of the CHEMKIN II package which has been slightly modified for incorporating the electron dissociation mechanism and conditions of constant plasma parameters in a plasma column flowing inside a tubular reactor. This 2D-model takes into account the coupled hydrodynamics of the gaseous species, gas phase chemistry and surface recombination at the reactor wall. The results are compared to the MBMS experimental results of the gaseous composition in the plasma as a function of various parameters. These experimental and modelling studies are used for correlating the influence of the relative concentration of important gaseous species in the plasma (especially radicals) to the deposition domain, the growth rate, the structure (polycrystalline or nano-smooth) and the diamond quality of the deposits. The influence of the concentrations of both hydrocarbon radicals and H and OH species in the plasma is especially evidenced together with their experimental concentration gradients in front of the growing surface. The growth of nano-smooth diamond films, with roughness in the 7-30 nm range, relatively to polycrystalline ones is explained and the variation of their intrinsic properties correlated.
Time Period MoA Sessions | Abstract Timeline | Topic B Sessions | Time Periods | Topics | ICMCTF2009 Schedule