Reaction paths and kinetics of aluminide formation in Al/epitaxial-W(001) model diffusion barrier systems
Single‐crystal bcc W(001) layers, 140 nm thick, were grown on MgO(001) substrates by ultrahigh‐vacuum (UHV) magnetron sputter deposition at Ts=600 °C. Al overlayers, 190 nm thick with strong (001) and (011) preferred orientation and an average grain size of 200 nm, were then deposited at Ts=100 °C without breaking vacuum. Changes in bilayer sheet resistance Rs were monitored continuously as a function of time ta and temperature Ta during UHV annealing. In addition, Rutherford backscattering spectroscopy, x‐ray diffraction, transmission electron microscopy (TEM), and scanning TEM, in which cross‐sectional specimens were analyzed by energy‐dispersive x‐ray analysis with a 1 nm resolution, were used to follow area‐averaged and local interfacial reaction paths as well as microstructural changes as a function of annealing conditions. The initial reaction products were discontinuous regions of monoclinic‐structure WAl4 which exhibit a crystallographic relationship with the underlying W layer. bcc WAl12 forms at...
Influence of Cu as an impurity in Al/Ti and Al/W thin‐film reactions
Thin‐film reactions of Al/Ti and Al/W with 3 at. % Cu in Al were investigated by glancing‐angle x‐ray diffraction and Rutherford backscattering for vacuum annealing in the temperature range 300–500 °C. In the Al/Ti system, the intermetallic phase Al3Ti grows as (time)1/2. The presence of Cu in Al retards the growth rate by an order of magnitude at 400 °C and increases the activation energy from 1.8±0.1 to 2.4±0.1 eV. In the Al/W system, the presence of Cu retards the penetration of W into Al.
Development of Science and Technology in the Iranian Electric Power Industry: Challenges and Future Progress
This chapter examines four key segments of the electric power industry in Iran: generation, transportation, distribution and consumption. It reviews the method, development, and evolution of electric power generation in the country. Specifically, the chapter reviews the structure of the electric industry, the main players, institutions, standards as well as laws, human resources, technology, the export and import markets, and engineering management of the industry in the country. Finally, the challenges facing the industry will be identified and policy suggestions to remedy the problems will be provided.