Thermal and Electrical Properties of PVD Ru(P) Film as Cu Diffusion Barrier

Thermal and electrical properties of physical vapor deposition (PVD) Ru(P) film deposited on porous ultra low-k (p-ULK) material as Cu diffusion barrier were studied. The phosphorous concentration can be tuned by adjusting Ar to PH₃ ratio of the sputtering gases. The leakage current depends on phosphorous concentration. Higher phosphorous content in Ru film has lower leakage current. No obvious phosphorous content dependence was observed when the amorphous Ru(P) film crystallized. The X-ray diffraction (XRD) graphs and energy dispersive spectrometer’s (EDS) atomic depth profiles show that the Ru(P) film deposited on p-ULK can effectively block Cu diffusion when the sample is subjected to 800 °C 5 min annealing. The phosphorous doped Ru film improves diffusion barrier properties and leakage current performance. The improved Ru(P) barrier capable of direct Cu plating could be a potential candidate for advanced metallization.     

Variation of structure and mechanical properties of Ti–6Al–4V with isothermal hydrogenation treatment

Grain refinement of Ti–6Al–4V (Ti64) was achieved by means of nucleation and growth of hydride phases associated with repeated isothermal hydrogenation (RIH). With a hydrogen loading of 0.7 H/M at 600 °C, a refined nanostructure (～50 nm) in the α matrix resulted mainly from the formation of platelet β_H and δ by the RIH treatment. The first cycle of RIH significantly increased the hardness and yield compressive stress, but further RIH cycling became less effective. For RIH with a hydrogen loading of 0.5 H/M at 750 °C, the refined structure was eliminated, and the compressive yield stress and microhardness of Ti64 were lowered.     

Heat transfer in a PEMFC flow channel

A numerical method was applied to the heat transfer performance in the flow channel for a proton exchange membrane fuel cell (PEMFC) using the finite element method (FEM). The heat transfer enhancement has been analyzed by transversely installing a baffle plate and a rectangular cylinder to manage flow pattern in the flow channel of the fuel cell. Case studies include baffle plates (gap ratios from 00.05 to 0.2) and the rectangular cylinder (width-to-height ratios from 0.66 to 1.66 with a constant gap ratio of 0.2; various gap ratios from 0.05 to 0.3 with a constant width-to-height ratio 1.0) at constant Reynolds number. The results show that the transverse installation of a baffle plate and a rectangular cylinder in the flow channel can effectively enhance the local heat transfer performance of a PEMFC. The installation of a rectangular cylinder has a better effective heat transfer performance than a baffle plate; the larger the width of the cylinder is the better effective heat transfer performance becomes.     

Comparison of five PCR methods for detection of Helicobacter pylori DNA in gastric tissues

Five different PCR methods for the detection of Helicobacter pylori were evaluated. The results of this study indicate that of the five PCR methods examined, the ureC (glmM) gene PCR is the most sensitive and specific for the detection of H. pylori in gastric biopsy specimens.     

Camphene as a novel solvent for polypropylene: Comparison study based on viscous behavior of solutions

Polypropylene solutions were prepared using three solvents: paraffin oil, decalin, and a novel solvent—camphene. The effects of these solvents were evaluated based on the activation energy of flow and on their melting‐point depression. Experimental results indicate that the values of the viscosity of the resulting solutions were close to Newtonian behavior in the shear rates below 34 s⁻¹. The Arrhenius–Frenkel–Eyring equation was used to describe the dependence of the viscosity on the temperature. In addition, the viscosity increased with the polymer concentration, which can be described by a power‐law correlation. The activation energy of the flow of the polypropylene/camphene solution was the lowest and that of the paraffin oil solution was the highest. Correspondingly, the melting‐point depression of polypropylene solutions in camphene and decalin were substantially lower than that in paraffin oil (71, 61, and 33°C, respectively). These results indicate that lower activation energies of flow correspond to higher values of melting‐point depression. Moreover, analysis of variance indicated that the primary factor affecting the viscous behavior is the concentration, followed by the solvent and the temperature. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 2068–2074, 2000     

Amorphization of Ti1−x Mn x

Three amorphous Ti_1−x Mn _x alloy powders, withx = 0.4, 0.5, and 0.6, were prepared by mechanical alloying (MA) of the elemental powders in a high-energy ball mill. The amorphous powders were characterized by X-ray diffraction (XRD) and high-resolution transmission elec- tron microscopy (HRTEM). The crystallization temperatures for these alloys detected by dif- ferential scanning calorimetry (DSC) varied from 769 to 830 K. The calculated enthalpies of mixing in these amorphous phases are relatively small compared with those for other Ti-base binary alloys. The criteria for solid-state amorphization reaction are examined. It is suggested that the kinetics of nucleation and growth favors the formation of the amorphous phases and the supply of atoms for nucleation and growth is predominantly through the defective regions induced by MA. Formerly Graduate Student, National Tsing Hua University     

Enhanced negative substrate bias degradation in nMOSFETs with ultrathin plasma nitrided oxide

The degradation induced by substrate hot electron (SHE) injection in 0.13-/spl mu/m nMOSFETs with ultrathin (/spl sim/2.0 nm) plasma nitrided gate dielectric was studied. Compared to the conventional thermal oxide, the ultrathin nitrided gate dielectric is found to be more vulnerable to SHE stress, resulting in enhanced threshold voltage (V/sub t/) shift and transconductance (G/sub m/) reduction. The severity of the enhanced degradation increases with increasing nitrogen content in gate dielectric with prolonged nitridation time. While the SHE-induced degradation is found to be strongly related to the injected electron energy for both conventional oxide , and plasma-nitrided oxide, dramatic degradation in threshold voltage shift for nitrided oxide is found to occur at a lower substrate bias magnitude (/spl sim/-1 V), compared to thermal oxide (/spl sim/-1.5 V). This enhanced degradation by negative substrate bias in nMOSFETs with plasma-nitrided gate dielectric is attributed to a higher concentration of paramagnetic electron trap precursors introduced during plasma nitridation.     

Cracking kinetics of two-phase stainless steel alloys in hydrogen gas

The kinetics of hydrogen-induced slow crack growth (SCG) under constant load was studied in two stainless steel alloys containing mixtures of bcc and fcc phases. FERRALIUM 255, a duplex stainless steel, consisting of ∼50 pct austenite in a ferrite matrix, was tested in hydrogen gas at 0 to 100 °C with the loading axis both perpendicular and parallel to the rolling direction. In addition, specimens of AISI 301 were deformed in air in different ways to produce various amounts of bcc phase in an austenite matrix prior to testing in H₂ gas at room temperature. The kinetics of subcritical slow crack growth (SCG) in these alloys was compared with that for austenitic and for ferritic stainless steels. The SCG rates were rationalized in terms of differences in hydrogen permeation in the two phases. The results confirm that a higher rate of supply and accumulation of hydrogen in the region ahead of the crack tip allows a higher cracking velocity.     

Newly established MST-1 tumour cell line and tumour-infiltrating lymphocyte culture from a patient with soft tissue melanoma (clear cell sarcoma) and their potential applications to patient immunotherapy

The establishment and characterisation of paired autologous tumour cell line (MST-1) and tumour-infiltrating lymphocyte (TIL) culture from a tumour mass of a 14-year-old Taiwanese girl with soft tissue melanoma are described. MST-1 cells grown in vitro were heterogeneous in morphology, ranging from floating round cells, loosely attached round/oval or elongated cells with prominent pseudopod-like processes, to well-attached spindle and elongated dendritic cells without obvious pseudopods. Immunostaining revealed that major melanoma-associated antigens, such as S100 protein, HMB-45, melanotransferrin, chondroitin sulphate proteoglycan, and the gangliosides GD2 and GD3, were consistently expressed by the tumour tissue, severe combined immunodeficiency (SCID) mouse xenograft and derived cell lines. Flow cytometric analysis of the tumour DNA content showed an index of 1.8 relative to normal peripheral blood lymphocyte DNA. Chromosome analysis revealed all cells at a hypotetraploid level with several clonal chromosome aberrations, including deletions at 10p and 12q, an addition at 12q, translocations t(1;14) and t(5;6). Electron microscopy showed melanosome structures. This observation and the expression of the major melanoma-associated antigens were all indicative of the melanocytic origin of MST-1 tumour. Interleukin-2 (IL-2) expanded TILs had the predominant CD8+ phenotype and the capacity to lyse cells of the cultured autologous tumour. The availability of the soft tissue melanoma cell line, the SCID mouse xenograft tumour system as well as autologous TILs described herein would provide useful materials for identifying T-cell-defined antigens as well as a model system for devising individualised cancer biotherapeutic strategies. This cell line can also be used for further studies aimed at uncovering the histogenesis of this rare cancer.     

LES analysis of turbulent flow and heat transfer in motored engines with various SGS models

This paper presents the application of three different subgrid-scale (SGS) models in a large eddy simulation (LES) for investigating the turbulent flow field and wall heat transfer during the compression-expansion strokes in two types of engine configuration under realistic engine conditions. Predictions were compared with experimental measurements (including the local heat flux and swirl velocity), and with those calculated from the conventional K-ε model. The results of the Van Driest wall damping model for LES were found to be in the best agreement with experimental data. The variations of velocity vector plots, isothermal profiles with crank angle were realized in the “Pancake” chamber engine. The variation of squish strength in the cylinder was also investigated by illustrating the friction velocity variations at different radial locations in the “Deep Bowl Piston” engine.