Papers

ICMCTF2009 Session F1-1: Advances in Characterization of Coatings and Thin Films

Tuesday, April 28, 2009 1:30 PM in Room Sunrise

Tuesday Afternoon

Start	Invited?	Item
1:30 PM		F1-1-2 Effect of Stoichiometry on Structure and Texture of Zr_1-xSi_xN Thin Films X. Zhang, M.S. Byrne, R.J. Lad (University of Maine) A series of zirconium silicon nitride (Zr_1-xSi_xN) thin films were grown on r-plane sapphire substrates using rf magnetron co-sputtering of Zr and Si targets in a N₂/Ar plasma. X-ray diffraction pole figure analysis, x-ray reflectivity, x-ray photoelectron spectroscopy, atomic force microscopy, and optical absorption spectroscopy were used to characterize the film stoichiometries and structures after growth at 200°C and following annealing up to 1000°C in vacuum. ZrN films grow with high quality (100) heteroepitaxy on r-sapphire, but the addition of Si up to x=15% induces film strain and causes the films to adopt a polycrystalline structure with (100) fiber texture. For x>15%, the films are amorphous even after vacuum annealing at 1000°C. XPS spectra and x-ray reflectivity data indicate that the Zr-Si-N films at all stoichiometries are very homogeneous. AFM revealed that 150 nm thick films have a roughness on the order of 1 nm, except for Si stoichiometries corresponding to where the film transforms from polycrystalline to amorphous structure. At this transition, evidence was found for regions of film delamination and hillock formation, which is presumably driven by strain at the film-substrate interface. UV-visible absorption spectra also were found to depend on the Si content. For Si-rich films (x>15%), the absorption edge and band gap are directly proportional to the Si content, whereas for Zr-rich films (x<15%), there is no band gap and the films are highly conductive.
1:50 PM		F1-1-4 Atom Probe Tomography of Thin Films D. Larson (Imago Scientific Instruments) Atom probe tomography can provide 3-D atomic-scale structural and compositional analysis of materials difficult to duplicate using other high-performance microscopy techniques. Recent specimen fabrication techniques using focused-ion beam instruments with in-situ manipulation now allows a variety of nanoscale thin films with site-specific features to be prepared and analyzed using atom probe tomography. This talk will address the fabrication and atom probe analysis, as well as comparison to other characterization techniques, of the microstructure of a variety of nanomagnetic thin film devices including multilayers, spin valves and tunnel barriers, and quantum well layered features.
2:30 PM		F1-1-6 Three-Dimensional Atom Probe Tomography of Nanocomposite Diamond-like Carbon Films T.W. Scharf, M.C. Romanes, R. Banerjee (The University of North Texas); R.D. Evans, G.L. Doll (Timken Company) Three-dimensional atom probe tomography (3DAP) studies have been carried out on hydrogenated diamond-like carbon (DLC) films. Nanocomposite tungsten carbide (predominately cubic β-WC_1-x phase) in mixed amorphous DLC sp³/sp² C-H matrices were characterized using the combination of HAADF STEM imaging and local electrode atom probe (LEAP) techniques. Alternating ~25 nm thick carbon-rich and tungsten-rich DLC layers were observed by HAADF STEM imaging while HRTEM in the tungsten-rich layers revealed well dispersed, nanocrystalline WC (~2–4 nm) precipitates throughout the amorphous C-H matrix. Excellent correspondence in the chemical layering was observed with 3DAP which also revealed atomic-scale composition containing carbon and hydrocarbon-rich fragments (C₃²⁺ and C₂H₄⁺) and tungsten and elemental carbon fragments (W²⁺, WC²⁺, C⁺ and C²⁺) in the carbon-rich and tungsten-rich layers, respectively. 3D morphology and chemical partitioning of the WC nanoprecipitates in the tungsten-rich layers will also be presented. The role of structure, phase distribution, and chemistry at the atomic and nanometer scales in controlling the tribological and mechanical properties at the macroscale will also be discussed.
2:50 PM		F1-1-7 Tip Enhanced Raman Spectroscopy for High Resolution Assessment of Strained Silicon Devices L. Sanderson, P. Dobrosz, S.H. Olsen, S.J. Bull (Newcastle University, United Kingdom); S. Mantl, D.M. Buca (FZ-Juelich, Germany) Due to aggressive scaling of semiconductor devices, strained silicon technology is an attractive option in the semiconductor industry in order to keep technology improving at a steady rate. Introducing a strained layer into the channel region of a device enhances transport mechanisms by improving hole or electron mobilities. The amount of strain induced in a device requires close monitoring as a function of processing since relaxation processes may occur. Raman Spectroscopy is a well-known technique for characterising the strain in strained Si/SiGe devices but the spatial resolution of this technique is limited by the laser spot size to between 0.5 - 1µm. Typically current strain measurement requirements are at the scale of about 50nm. Tip Enhanced Raman Spectroscopy (TERS) is a technique which exhibits large signal enhancements as well as a greatly improved spatial resolution allowing much smaller device features to be measured with some accuracy. TERS makes use of the localised surface plasmons produced by a metallised AFM tip to create a large electric field enhancement in the vicinity of the tip apex, improving the spatial resolution to the nanometre range (or that of the tip’s diameter). This paper reports the strain profiling of Strained Silicon on Insulator (SSOI) stripes of various widths in the nanometre range using TERS. The stripes were fabricated in such a way that pseudo-uniaxial strain was induced to improve hole mobility. Finite Element simulation results show good agreement to the experimental work. This work illustrates the potential of TERS to become a powerful submicron in-situ characterisation technique.
3:10 PM		F1-1-8 Depth Profile Analysis of Thin Layers on Glasses and Ceramics by RF GD OES P. Hunault (Horiba Jobin Yvon Inc.); P. Chapon, C. Tauziede, A. Tempez (Horiba Jobin Yvon Inc., France); M. Ganciu (NILPRP - Bucharest, Romania); P. Guillot (University JF Champollion - Albi, France); P. Belenguer (Laplace CNRS, France) Radio Frequency Glow Discharge Optical Emission Spectrometry (RF GD-OES) is an established technique capable of Ultra Fast Elemental Depth Profiling of thin films down to the nanometre. The application of the technique to the characterisation of thin layers on glasses and ceramics is investigated. Issues related to heat and thermal damage as well as coupling efficiency are shown and solutions to overcome these issues are presented resulting from theoretical and experimental characterisations of the RF GD plasma and of its interaction with the material surface. The new RF coupler that is now available allows sputtering of up to 5mm thick glasses or ceramics and provides adequate performances for valuable analysis of such materials as examples from solar cells and coated ceramics will illustrate.
3:30 PM		F1-1-9 Local-Order Information of the Decomposition of Nanocrystalline Supersaturated TiAlN by X-ray Absorption Spectroscopy J. Endrino, R. Gago (Instituto de Ciencia de Materiales de Madrid, Spain); G. Fox-Rabinovich (McMaster University, Canada); A. Gutierrez (Universidad Autonoma de Madrid, Spain) Even though the decomposition of supersaturated metastable TiAlN with NaCl-type structure (c-TiAlN) upon annealing has been the subject of considerable research effort in the last decade, the evolution of the local electronic structure with annealing temperature is largely unknown. Thus far, phase transformation into coherent cubic domains has been explained by the spinodal decomposition of the metastable c-TiAlN phase upon annealing, although Al content and distribution, together with structural disorder, can play a significant role in the compound evolution and stability upon annealing. Synchrotron radiation spectroscopic techniques offer an opportunity of providing local-order information of the phenomena with site-selective information. In this study, we present X-ray absorption near edge structure (XANES) spectra of the Ti-K, Al-K, and N-K edges of supersaturated TiAlN samples annealed between 700ºC and 900ºC. Thermal treatments in this temperature range lead to the formation of coherent cubic nanocrystallites with no detrimental hexagonal phase segregation, as observed by high-resolution transmission electron microscopy and electron diffraction patterns. XANES corroborates this structural information at a local order. Further, the origin of the XANES spectral features is further investigated by using resonant inelastic X-ray scattering (RIXS) near the N K-edge.
3:50 PM		F1-1-10 Testing Thin Films by Microcompression: Benefits and Limits D. Kiener, H.P. Woergoetter (Erich Schmid Institute of Materials Science, Austria); G. Dehm (University of Leoben, Austria) Coatings are very important for numerous industrial applications such as increasing the wear resistance of tools, providing thermal conductivity to components in engines or electric conductivity in microelectronic devices. The mechanical properties of the coatings are of prime concern. The practicability of performing miniaturized compression tests in order to determine mechanical properties of various thin films was analysed. Four coatings, a polycrystalline tungsten coating, a single crystal copper coating and two single crystal hard coatings (vanadium nitride and titanium nitride) were tested. The compression samples were fabricated using a focused ion beam microscope. The compression tests were executed with a micro-indenter installed in a scanning electron microscope. The deformation of the sample was observed and in-situ recorded by scanning electron microscopy. From the measured load-displacement data true stress-true strain curves were calculated. The limits and benefits of the microcompression technique are discussed.
4:10 PM		F1-1-11 Contact Angle Analysis of Sol-Gel Derived Zirconia Based Hybrid Coatings on 304 Stainless Steel Substrates S. Ashokkumar, J. Hinke (Accoat A/S, Denmark); J.A. Nissen, P. Moller (Technical University of Denmark) Sol-gel derived hybrid coatings were prepared from 3-Glycidoxypropyltrimethoxysilane (GPTMS), tetraethoxysilane (TEOS) and tetra-n-propoxy zirconium (TPOZ) precursors on 304 stainless steel substrates by dip and spray coating methods. The influencing parameters such as precursor ratio, number of dippings, stirring time and temperature on the morphology, chemical composition and contact angle of the coatings were studied. The chemical composition and surface morphology of the coatings have been analyzed by XPS and SEM. The contact angle measurement were made manually by delivering a 4µmlitre drop of triple distilled water from a microsyringe onto the surface of the sample plate (10x10x1mm) placed on a horizontal stage. The photo of the static water droplet was captured by a digital video camera of high resolution equipped with TECHSPEC Silver series Telecentric measuring lense. The measurement of the contact angle was made with a program called DropSnake. Mea surements were repeated five times with new drops at different positions on the sample. The reported contact angles are the average value of the five measurements. Contact angles have an estimated accuracy of +-2 degrees.The coating prepared by dip coating method with an inorganic precursor containing tetra-n-propoxy zirconium (TPOZ) and ethylacetoacetate volume ratio of 1:1 at 55 degree celsius with a stirring time of 2 hours exhibited a higher contact angle of 79.4° when compared to coatings prepared with other different conditions.