Copper-based metallization has recently attracted extensive research because of its potential application in ultra-large-scale integration (ULSI) of semiconductor devices. The feasibility of copper metallization is, however, limited due to its thermal stability issues. In order to utilize copper in metallization systems diffusion barriers such as titanium nitride and other refractory materials, have been employed to enhance the thermal stability of copper. Titanium nitride layers can be formed by annealing Cu(Ti) alloy film evaporated on thermally grown SiO2 substrates in an ammonia ambient. We report here the microstructural evolution of Cu(Ti)/SiO2 layers during annealing in NH3 flowing ambient.The Cu(Ti) films used in this experiment were prepared by electron beam evaporation onto thermally grown SiO2 substrates. The nominal composition of the Cu(Ti) alloy was Cu73Ti27. Thermal treatments were conducted in NH3 flowing ambient for 30 minutes at temperatures ranging from 450°C to 650°C. Cross-section TEM specimens were prepared by the standard procedure.
Short-circuit Current Reduction in Auxiliary Network of Traction Substations