Materials Science Forum Vols. 561-565

Abstract: Plasma-generation and control technologies for meters-scale ultra-large-area RF plasma sources have been developed with multiple low-inductance antenna (LIA) modules, as a promising candidate of ultra-large area and high-density (1011-1012 cm-3) plasma sources for next-generation large-area processing. The present technologies are based on principle of multiple operation and integrated control of LIA modules, which enables effective control of power deposition profiles and hence the plasma uniformity over meters-scale large area for processing. This paper presents issues in designing ultra-large-area plasma sources to demonstrate feasibility of the uniform sources with 3m x 3m scales to meet requirements in the next-generation processes.

Abstract: In order to determine an effective coating film for cutting carbon steels with a coated cemented carbide tool, tool wear was experimentally investigated. Low carbon steel (AISI 5120H steel) was turned with four kinds of physical vapor deposition (PVD) coated cemented carbide tools. The coating films used were TiN coating film and three kinds of titanium-tungsten-silicon-aluminum based coating films, namely (Ti,W,Si,Al)N, (Ti,W,Si,Al)C and (Ti,W,Si,Al)(C,N) coating film. (Ti,W,Si,Al)N, (Ti,W,Si,Al)C or (Ti,W,Si,Al)(C,N) is a new type of coating film. The following results were obtained: (1) The critical load of three kinds of titanium-tungsten-silicon-aluminum based coating films was higher than that of TiN coating film. (2) The hardness of three kinds of titanium-tungsten-silicon-aluminum based coating films was higher than that of TiN coating film. (3) In cutting low carbon steel, the wear progress of three kinds of titanium-tungsten-silicon-aluminum based coating film tools was slower than that of the TiN coated tool. (4) In the three kinds of titanium-tungsten-silicon-aluminum based coating films, the wear progress of the (Ti,W,Si,Al)N coated tool was the slowest.

Abstract: Thin films of hydrogenated silicon-oxycarbide (a-SiOCx:H) have largely replaced pure silicon oxide films as back end of line (BEOL) processing in Ultra Large Scale Integrate Circuit (ULSI). A single chamber system for hot wire chemical vapor deposition (HWCVD) was employed to deposit different films of a-SiOCx:H with 0.5 < x < 0.8. All films were characterized by infrared spectroscopy and X-ray photoelectron spectroscopy (XPS) to determine the stoichiometry and the presence of various bonding configurations of constituent atoms. We used X-ray reflectivity (XRR) and Small angle X- ray scattering (SAXS) to determine the porosity and inhomogeneities (clustering) in the films.

Abstract: Preparation of nanocrystalline 430L stainless steel powders by high-energy ball milling has been investigated. The samples were characterized by scanning electron microscope (SEM), X-ray Diffraction (XRD) and Matersizer. The SEM observation confirmed that the cold welding and fragmentation behaviors occurred during high-energy ball milling, which has important effect on the changes of the particle size. In the initial stage (0-10h), particle size increased and crystalline grain size decreased evidently. The mean particle size got to 330μm and the crystalline grain size got to 23nm for sample of 10h ball milling. In the later stage, the particle size decreased and the refinement of crystalline grain became difficult. The crystalline grain size of sample for 50h ball milling only got to 15nm.

Abstract: ZnO nanoparticles were carried out by Microemulsion method in the presence of TritonX-100 (poly oxyethylene tert-octylphenyl ether) as a surfactant. X-100/n-hextnol/cyclohexane/ waterW/O microemulsion system was also determined. Zinc chloride (ZnCl2·2H2O) and ammonia (NH3·H2O) were used as raw materials. The results indicated that the formation of ZnO nanoparticles was confirmed, using X-ray diffractometer (XRD) and transmission electron microscopy (TEM). The results showed that the nanoparticle was exactly ZnO with wurtzite type crystalline structure and the size of nanoparticles is strongly affected by the ratio of water to surfactant(R). With the R value increase, the particles size became larger.

Abstract: The quantitative study for the stability of local atomic structures in bulk metallic glasses (BMGs) with temperature effect on physical quantities of BMGs needs the molecular dynamics simulation with the reliable interaction parameter model such as the Embedded-atom-method potentials (EAMPs) which reproduce the ab-initio data as well as the experimental data. We present the ab-initio data for inter-atomic interactions of Zr-rich ZrCu alloys and a preliminary result for the EAMPs of Zr-rich ZrCu alloys.

Abstract: Ca65Mg15Zn20 bulk metallic glass samples of dimensions 3.15 × 7 × 125 mm were prepared using an inverted low-pressure die-casting technique. It was found that charge temperature, and injection pressure were important parameters for controlling the length, porosity and degree of crystallinity in the as-cast samples. A processing map was generated illustrating the optimum casting temperature and pressure range for generating the highest quality castings. These samples were ground into tensile samples in compliance with ASTM E8-04 and deformed in the supercooled liquid (SCL) region (105 to 135 °C) at constant strain rates from 10-3 to 10-4 s-1. Reported are the effects of these parameters on the deformation behaviour of the Ca65Mg15Zn20 BMG.

Abstract: Ternary Sm-Al-Co bulk metallic glass formation is investigated with the guidance of a cluster line approach which is defined by linking a special cluster composition to the third element in the ternary phase diagram. Two dense-packed cluster lines Sm6Al3Co2-Co and Sm8Al1Co4-Al are constructed and they intersect at a good BMG composition Sm50Al25Co25. This composition can also be interpreted with a cluster-plus-glue atom model. The characteristic parameters of this optimum BMG are respectively Tg = 579 K, Tx = 640 K, Trg= 0.648, γ = 0.435 and
E=244 kJ/mol.

Abstract: Viscous flow behavior in supercooled liquid region of as-cast and pre-annealed Zr55Cu30Al10Ni5 bulk metallic glasses has been examined by using a penetration viscometer under high-speed heating rate of 20, 200 and 400 °C/min. Applied load for the cylindrical-shaped penetration indenter with a diameter of 1 mm was varied from 0.049 N to 0.294 N. Viscosity was quite independent of these applied loads. By pre-annealing the bulk metallic glasses at 400 °C, the density of the glasses increased, while the viscosity and the activation energy for viscous flow in their soopercooled liquid decreased with the pre-annealing treatments. Corresponding measurements of the differential thermal calorimetry (DSC) have been also done.

Abstract: The present paper investigates the bulk metallic glass formation in Co-based alloy systems with the guidance of the cluster line and minor-alloying principles. The selected basic ternary Co-B-Si alloy compositions are intersecting points of cluster lines, defined by linking special binary clusters to the third element. Then these basic ternary alloys are further minor-alloyed with Nb and quaternary bulk metallic glasses are obtained only by 4-5 at. % Nb minor-alloying of the basic composition Co68.6B25.7Si5.7 that is developed from dense-packed cluster Co8B3. The bulk metallic glasses are expressed approximately with a unified simple composition formula: (Co8B3)1(Si,Nb)1. In addition, a quantity of Fe substitution for Co further improves the glass-forming abilities.