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In this chapter, electromigration is formulated as a phenomenon of mass transport in metals under an electrical current driving force within the framework of irreversible thermodynamics. Based on this approach, the solute effect on electromigration is analyzed by considering the correlation in atomic jumping processes, a problem that is of interest to understand how solute addition can affect electromigration in metals. This is followed by a review of the theory of the electromigration driving force and a discussion of the controversy of the electron screening effect. This chapter is concluded by reviewing the results on substitutional and interstitial electromigration in bulk metals.
This chapter first showed how electromigration for the on-chip interconnects is distinctly different from that of bulk metals. As the microelectronics technology rapidly advances following Moore’s law, electromigration becomes a key reliability problem for on-chip interconnects. This significantly changes the characteristics of electromigration, rendering thermal stresses as equally important in controlling mass transport and damage formation in the interconnects. This led to the discovery of the Blech short-length effect, establishing the concept of a critical current density-length (jLc) product as an important reliability criterion for on-chip interconnects. In this chapter, thermal stress characteristics and stress-induced void formation in passivated Al and Cu lines are investigated. The effect of dielectric confinement on thermal stress characteristics is discussed and verified by results of X-ray diffraction measurements of passivated Al and Cu lines. Then stress relaxation in passivated Al and Cu lines is discussed and correlated to stress-induced void formation.
In the present work, LaNi0.5Ti0.5O3, LaNi0.5Ti0.45Co0.05O3, and LaNi0.45Co0.05Ti0.5O3 perovskites were synthesized using the modified Pechini method. After reduction, the studied perovskites changed crystal structure from the perovskite crystal structure to a cubic symmetry, with space group $Pm\bar{3}m$. The reduction partially decomposed the samples to Ni0 (Co free perovskite), Ni0–Co0, La2O3, La2TiO5, and non-stoichiometric La2NiO4, depending on H2 content of the reductive gases. The degree of reduction of nickel from LaNi0.5Ti0.5O3 reduced with 1.8% H2/Ar and 10% H2/Ar was equal to 36.5% and 95.3%, respectively, while that from LaNi0.5Ti0.45Co0.05O3 or LaNi0.45Co0.05Ti0.5O3, including cobalt, reduced with 10% H2/Ar, was equal to 71.9% and 93.9%, respectively. LaNi0.5Ti0.45Co0.05O3 showed Ni3+ and Co3+ amounts higher than the other perovskites. By increasing H2 content in the reductive mixture from 1.8% to 10%, sintering of metallic nickel was not observed. Moreover, Ni0 displayed weaker metal–support interaction than that observed for Co0, where the support was composed of La containing oxides. LaNi0.5Ti0.5O3 perovskite was used as a catalyst for steam reforming of methane. Syngas production was attributed to the number of Ni sites determined using Rietveld Refinement of X-ray diffraction pattern of this catalyst after the reaction.
X-ray powder diffraction data for the two new polymorphs of 1-methylhydantoin, C4H6N2O2, are reported. The polymorph II (MH-II) crystallizes in the orthorhombic system with space group Pna21 [a = 19.0323(7) Å, b = 3.91269(8) Å, c = 6.8311(7) Å, Z′ = 1, Z = 4, unit cell volume V = 508.70(3) Å3. Polymorph III (MH-III) crystallizes in the orthorhombic system with space group P212121 [a = a = 7.82427(5), b = 9.8230(5), c = 20.2951(4), Z′ = 3, Z = 12, unit cell volume V = 1563.5(1) Å3]. All measured lines, in each case, were indexed and are consistent with the space group.
Learn to assess electromigration reliability and design more resilient chips in this comprehensive and practical resource. Beginning with fundamental physics and building to advanced methodologies, this book enables the reader to develop highly reliable on-chip wiring stacks and power grids. Through a detailed review on the role of microstructure, interfaces and processing on electromigration reliability, as well as characterisation, testing and analysis, the book follows the development of on-chip interconnects from microscale to nanoscale. Practical modeling methodologies for statistical analysis, from simple 1D approximation to complex 3D description, can be used for step-by-step development of reliable on-chip wiring stacks and industrial-grade power/ground grids. This is an ideal resource for materials scientists and reliability and chip design engineers.
Exact and approximate mathematical models for the effects of sample transparency on the powder diffraction intensity data are examined. Application of the formula based on the first-order approximation about the deviation angle is justified for realistic measurement and computing systems. The effects of sample transparency are expressed by double convolution formulas applying two different scale transforms, including three parameters, goniometer radius R, penetration depth μ−1, and thickness of the sample t. The deconvolutional treatment automatically recovers the lost intensity and corrects the peak shift and asymmetric deformation of peak profile caused by the sample transparency.
We have grown intermetallic ErPd2Si2 single crystals employing laser diodes with the floating-zone method. The temperature dependence of the unit-cell parameters was determined using synchrotron and in-house X-ray powder diffraction measurements from 20 to 500 K. The diffraction patterns fit well with the tetragonal I4/mmm space group (No. 139) with two chemical formulae within the unit cell. The synchrotron powder diffraction study shows that the refined unit-cell parameters are a = 4.10320(2) Å, c = 9.88393(5) Å at 298 K and a = 4.11737(2) Å, c = 9.88143(5) Å at 500 K, resulting in the unit-cell volume V = 166.408(1) Å3 (298 K) and 167.517(2) Å3 (500 K). In the whole studied temperature range, no structural phase transition was observed. Upon cooling, the unit-cell parameters a and c are shortened and elongated, respectively.
In this chapter the principles of composite manufacture are discussed. The advantages and disadvantages of each method are considered in identifying a process for a particular artefact. Specifically, the need to use sophisticated fibre placement techniques in manufacture is described.
In this chapter we describe the resins used for the manufacture of composite artefacts. The concept of curing is discussed with respect to the chemistry of typical polymer matrices. The advantages and disadvantages of thermosets and thermoplastics are also discussed.
In the case of thermosets, the importance of thermoplastic and rubber toughening is considered. While we concentrate on polymer matrix materials, ceramic and metal matrices are referred to for completeness.
In this chapter, the analysis in Chapter 6 is extended to dynamic loading. The main aim is to provide sufficient knowledge for predicting the life of a composite structure.