Copper diffusion in Ti-Si-N layers formed by inductively coupled plasma implantation

Ternary Ti-Si-N refractory barrier films of 15 nm thick was prepared by low frequency, high density, inductively coupled plasma implantation of N into Ti_xSi_y substrate. This leads to the formation of Ti-N and Si-N compounds in the ternary film. Diffusion of copper in the barrier layer after annealing treatment at various temperatures was investigated using time-of-flight secondary ion mass spectrometer (ToF-SIMS) depth profiling, X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and sheet resistance measurement. The current study found that barrier failure did not occur until 650 °C annealing for 30 min. The failure occurs by the diffusion of copper into the Ti-Si-N film to form Cu-Ti and Cu-N compounds. FESEM surface morphology and EDX show that copper compounds were formed on the ridge areas of the Ti-Si-N film. The sheet resistance verifies the diffusion of Cu into the Ti-Si-N film; there is a sudden drop in the resistance with Cu compound formation. This finding provides a simple and effective method of monitoring Cu diffusion in TiN-based diffusion barriers.     

AN IMPROVED SEARCH-EXTENTION METHOD FOR SOLVING SEMILINEAR PDES

This article will combine the finite element method, the interpolated coefftcient finite element method, the eigenfunction expansion method, and the search-extension method to obtain the multiple solutions for semilinear elliptic equations. This strategy not only grently reduces the expensive computation, but also is successfully implemented to obtain multiple solutions for a class of semilinear elliptic boundary value problems with non-odd nonlinearity on some convex or nonconvex domains. Numerical solutions illustrated by their graphics for visualization will show the efficiency of the approach.     

An Enhancement of the Drezner—Wesolowsky Algorithm for Single-Facility Location with Maximin of Rectilinear Distance

In this note, we examine the algorithm of Drezner and Wesolowsky for locating a facility with maximin rectilinear distance to a given set of demand points. The concept of the closest-point constraint is introduced as a technique for increasing the efficiency of the algorithm. This potential increase in efficiency is demonstrated by an example.     

Modelling treatment effects in the HIV/AIDS epidemic

Advances in recent treatments for HIV/AIDS patients have shown dramatic outcomes in extending the incubation period and AIDS survival time, while also providing significant improvements in the quality of patients' lives. A compartmental model is proposed to analyse the effects of the various treatment regimens which have been introduced. The results produced are in good agreement with routinely collected data relating to levels of HIV/AIDS incidence and prevalence in the UK homosexual population. Some parameter values within the model are obtained from surveys, census results, etc, but others are derived using a maximum likelihood estimation procedure. Finally, the model is used to project levels of incidence and prevalence over the next few years, and to investigate several possible scenarios.     

On local optima in multiobjective combinatorial optimization problems

In this article, local optimality in multiobjective combinatorial optimization is used as a baseline for the design and analysis of two iterative improvement algorithms. Both algorithms search in a neighborhood that is defined on a collection of sets of feasible solutions and their acceptance criterion is based on outperformance relations. Proofs of the soundness and completeness of these algorithms are given.     

A note on the acyclicity of the Koszul complex of a module

We prove the vanishing of the Koszul homology group H _μ(Kos(M)_μ), where μ is the minimal number of generators of M. We give a counterexample that the Koszul complex of a module is not always acyclic and show its relationship with the homology of commutative rings.     

Synthesis of double silylene-bridged binuclear titanium complexes and their use as catalysts for ethylene polymerization

Five new double silylene-bridged binuclear titanium complexes were synthesized by the reaction of RCpTiCl₃ and Li₂[μ,μ-(SiMe₂)₂ (C₅H₃)₂] in toluene. They were all well characterized. These complexes activated with methylaluminoxane (MAO) are highly active catalysts (2.33 × 10⁵ g PE/mol Cat h) for the polymerization of ethylene even at low Al/Ti (Al/Ti = 300). The molecular weight distribution of the polymer indicates broad or bimodal (MWD = 26.76) distribution.     

Corrigendum to the paper ``Adjoining an Order Unit to a Matrix Ordered Space'

An error has been detected (and also corrected) in Theorem 2.8 of the paper entitled “Adjoining an Order Unit to a Matrix Ordered Space” (Positivity, (2005)9: 207–223; DOI ). Accordingly, some of the results of the paper have been modified. Also, a notion of C*-matricially, Riesz normed spaces has been introduced.     

半导体反型层中的电子关联和多体波函数

本文运用CBF(correlation basis function) 理论, 由电子间的有效势V_eff_(R) 和电子气的集体振荡行为, 给出准二维电子体系— 半导体反型层中的电子的关联因予U (R), 得到该体系的对关联函数、关联能和多体波函数. 关键词：     

合肥同步辐射软X射线显微术研究

合肥国家同步辐射实验室首期建设的光束线之一用于软Ｘ射线显微成像研究。实验站现已装置初型的扫描透射Ｘ射线显微镜，并正在进行亲一代的扫描显微建设，同时还使同步辐射光进行接触软Ｘ射线呈微成像研究，并对选取的一些生物样品进行了成像试验。本文介绍了合肥同步辐射光源上软Ｘ射线显微术实验线站的建设及完成的一些实验结果。