Papers

ICMCTF2007 Session F1-2: Advanced Characterization / General Topics

Monday, April 23, 2007 1:30 PM in Room Sunset

Monday Afternoon

Start	Invited?	Item
1:30 PM		F1-2-1 SAXS Analysis of Graphitic Amorphous Carbon M.H. Oliveira Jr, P.F. Barbieri, I.C.L. Torriani, F.C. Marques (Universidade Estadual de Campinas, Brazil) We report on the study of amorphous carbon films using the small angle x-ray scattering (SAXS) technique. The films were deposited by ion beam assisted deposition (IBAD) using two Kauffman sources, one for sputtering a graphite target with xenon ion (1500 eV), and the other to simultaneously bombard the film with xenon ion with different ion energy, ranging from 80 eV to 200 eV. The film density was obtained from RBS measurements using the film thickness (of about 100 nm) determined by a stylus profilometer. It was observed that the film density increases with the assisting ion energy used during deposition. Small angle x-ray scattering, performed using light from a synchrotron (LNLS), revealed the presence of large scatter centers within the matrix, increasing in size with assisting ion energy. The gyration radius (R_g) are in the range of 18 to 25nm. However, the mean distance between those centers were found to be only of about 2.5nm independent of the deposition conditions. The fact that the R_g is larger than the distances between particles suggests that those particles are composed of planar graphitic clusters. These results are in agreement with Electron Energy Loss Spectroscopy (EELS) measurements, which reveal that the films are graphitic-like with about 80 to 90% of sp² hybridization. The sp² concentration depends also on the ion bombarding energy, increasing with ion energy.
1:50 PM		F1-2-3 Three-Dimensional Atom Mapping of Thin Films with Atom Probe Tomography T. Kelly (Imago Scientific Instruments Corporation) Atom probe tomography is the highest spatial resolution analytical technique. It provides three-dimensional structural and compositional analysis of materials at the atomic scale. With recent developments in LEAP® technology by Imago Scientific Instruments, the atom probe’s compositional imaging capabilities are now accessible to non-experts for analysis of a wide variety of materials including metals, magnetic media, semiconductors, ceramics, geological materials, and even synthetic organics and polymers. Specimen preparation advances have made it routine now to extract and analyze materials from wafers and even finished components. Important examples of analyses of metals, CMOS semiconductor structures and devices, thin-film multilayer structures, and organic nanostructures will be shown.
2:30 PM		F1-2-5 Analysis of Multilayer Biaxially Oriented Polypropylene (BOPP) Films Using the Technique of Nano-TA (Nanoscale Probe Based Thermal Analysis) N. Gotzen, G. Van Assche (Vrije Universtiatet, Belgium); W.K. King (Georgia Tech); K. Kjoller, R. Shetty (Anasys Instruments) Biaxially Oriented polypropylene (BOPP) films, both heat sealable and non-heat sealable are extensively used in the packaging industry. To our knowledge, no one has measured the Tg of the Skin layers directly in cross section and this is now possible with the nano-TA technique we are using whose results will be presented. The technique uses a breakthrough thermal probe of 20nm in tip diameter which enables us probe the skin layer's Tg directly. BOPP films are uni or multi-layered structures having a typical total thickness of only 15-25 ?m. The simplest multilayer films correspond to three-layer structures: one thick core layer of polypropylene homopolymer sandwiched between two thin (usually close to 1 ?m) skin layers. Each layer has its own contribution to the properties of the film. In the standard three-layer structures, the core layer mainly provides the rigidity of the film, whereas the skin layers provide sealing and/or surface properties [1]. The aim of our work was twofold: 1. To investigate the thermal properties of three-layer BOPP films and in particular to use nanoscale thermal analysis to investigate the transition temperature of the 1 ?m skin layer in cross-section for the first time. 2. To investigate the effect of ageing on the thermal properties of BOPP films. An additional goal was to compare the differences in measurement with a Wollaston wire probe (probe radius of around 2.5 micron by 25 microns) versus the nanoscale probe (probe radius of around 20 nm). The sub-100nm thermal analysis capability of the nano-TA system has enabled transition temperature measurements of the skin layer in the cross section of BOPP films for the first time. It is clearly demonstrated that the nano-TA system is more sensitive than the micro-TA system in measuring onset temperatures and showed more distinct differences in transition temperatures for the fresh and the annealed BOPP films.
2:50 PM		F1-2-6 Characterization of Plasma Sprayed TiB₂ Coatings with XRD, XPS and SEM J. Liu, G. Mertens, P.T. Jones, J. Elsen, B. Blanpain, P. Wollants (Katholieke Universiteit Leuven, Belgium) Titanium diboride has been the main component of most inert cathode concepts since it was introduced as a wettable cathode material in Hall-Héroult cells. However, for use as a bulk material, TiB₂ is not only too expensive, but it is also very brittle and sensitive to mechanical and thermal shock. Therefore, much effort has been made to find a suitable coating consisting of this material. TiB₂ coatings were plasma sprayed in air onto stainless steel substrates with different combinations of plasma spraying parameters in this study. The phase composition of the coating was investigated quantitatively by X-ray diffraction (XRD) analysis. The XRD data processing, based on the Rietveld method, made it possible to obtain good accuracy in the phase determination. It was shown that plasma spraying of TiB₂ in air results in the formation of oxides and nitride as well as TiB₂ which was the major phase. The composition and chemical state of titanium and boron in the surface layer have been investigated by the method of X-ray photoelectron spectroscopy (XPS). The sample surface consists of titanium, boron, carbon, nitrogen and oxygen; boron and titanium exists mainly as B₂O₃ and TiO₂. The microstructure of the coatings was studied by scanning electron microscopy (SEM).
3:10 PM		F1-2-7 Application of RF-GD-OES to the Analysis of Metallurgical Thin Films P. Hunault, P. Chapon, C. Tauziede (HORIBA Jobin Yvon, France); T. Nakamura (HORIBA, Japan) Radio Frequency Glow Discharge Optical Emission Spectrometry (RF-GD-OES) combines the ability to sputter conductive and non-conductive layers of materials at very high rates (1-3 µm/min) with minimum surface damage and no surface charging and it can achieve significant penetration depths (> 150 µm) with high resolving power (~1 nm or less) making it a suitable tool for research, process evaluation and production control of all metallurgical thin films. Various results will be presented including a record quantitative analysis of 107 layers of TiN/CrN, 20nm each, perfectly resolved. Even thinner layers down to the nm level, including of molecular layers adsorbed on surfaces. Recent instrument updates include the use of pulsed RF that extends the range of applications to thermally fragile layers as well as quantification software models as applied to ultra thin layers and surfaces. Finally the use of RF-GD as a preparation tool for Electron Microscopy will be illustrated.
3:30 PM		F1-2-8 Analysing of Thin Film Nanoindentation Data via Internetportal - The State of Realisation N. Schwarzer, M.C. Fuchs, L. Geidel, N. Bierwisch (Saxonian Institute of Surface Mechanics SIO, Germany) Due to the new analysing techniques using the Pharr's concept of the effectively shaped indenter a rather physical and comprehensive analysing of nanoindentation data of thin films is possible¹. Even in the case of very thin coatings well below 100nm thickness important physical mechanical parameters like Young's modulus, critical stresses for phase transition and Yield strength can be determined². However, as the mathematical apparatus for such analysing procedures is rather complex and the performance of the evaluation very cumbersome and difficult to learn, it seems reasonable to provide this type of calculation as a service within the internet. The present contribution is about the state of realisation of such a remote analysing service and first results. ¹N. Schwarzer, T. Chudoba, G. M. Pharr: "On the evaluation of stresses for coated materials during nanoindentation with sharp indenters", Surf. Coat. Technol, Vol 200/14-15 pp 4220-4226, http://dx.doi.org/10.1016/j.surfcoat.2005.01.011 ² N. Schwarzer, T. Chudoba, F. Richter: "Investigation of ultra thin coatings using Nanoindentation", Surface and Coatings Technology, Vol 200/18-19 pp 5566-5580, online at doi: http://dx.doi.org/10.1016/j.surfcoat.2005.07.075.
3:50 PM		F1-2-10 A Study on Microstructural Evolution in Nanocrystalline TiN Thin Films V. Chawla, R. Jayaganthan, R. Chandra (IIT Roorkee, India) TiN thin films are extensively used for tribological and diffusion barrier applications due to their superior hardness, and chemical stability. Nanocrystalline TiN thin film possesses enhanced hardness and strength as compared to its bulk microcrystalline thin films due to the nanoscale size effects. As the microstructural characteristics, especially the grain size and shape distributions, strongly influence the properties of nanocrytalline TiN thin films, it is essential to understand the grain growth kinetics, which control the evolution of microstructure. The driving forces for grain growth evolution of thin films are i) decrease in grain boundary free energy ii) decrease in surface strain energy. The aim of the present work was to investigate the grain growth evolution of Nanocrystalline TiN thin films using DSC, FE-SEM and HRTEM. TiN thin films were prepared on Si substrate by DC magnetron sputtering technique under various processing conditions. The phase and microstructural changes of nanocrystalline TiN films formed under different processing conditions are characterized. The formation of nanocrystals in microstructure of TiN thin film was confirmed by XRD and TEM. AFM was used to characterize surface topography of TiN thin films. The driving force for grain growth evolution of nanocrystalline TiN thin films was calculated using the enthalpy released or absorbed during heating and cooling cycle of DSC studies. Kissinger analysis was used to study the grain growth kinetics of TiN thin films using DSC data. It was observed that nanocrystalline TiN has higher driving force of grain growth when compared to that of its bulk counter part. However, the presence of impurities in trace amounts stabilizes the fine grain size of nanocrystalline TiN films due to Zener Drag effect. The influence of temperature, compositions, impurities, and processing parameters on the microstructrual evolution of TiN nanocrystalline thin films is quantified.
4:10 PM		F1-2-11 Non Destructive Nano-Mechanical Characterization of Thin Films N. Gitis, M. Vinogradov, I. Hermann, V. Khosla (CETR) Traditional techniques of destructive mechanical characterization for coatings reliability are limited to hardness, wear and scratch tests on a micro-level with balls or pins. Lately-popular nano-indentation allows for testing of thinner films but, is still destructive. Common AFM-based techniques use smaller tips but may not detect defects smaller than the sample roughness or the underlying hidden defects. A novel Nano-analyzer enables effective quantitative non destructive mechanical characterization of ultra-thin films. It can nondestructively measure Young’s modulus of ultra-thin films with a negligible substrate effect. Combining topographical and mechanical surface mapping, it allows for detailed nano-morphology and nano defectivity studies. This paper discusses in detail the comprehensive defect characterization of SiN and DLC coatings on glass and non homogeneity at Cu/Ni interface on bond wires in the packaging industry. In both the cases the coatings passed the defect/reliability testing with conventional methods only to find that they failed in real life. The case study describes how these failures/non homogeneity were revealed using new methodology. Future work is being carried on to categories the defects to understand and increase the reliability of the ultra thin coatings.