AINISSA RAMIREZ discovered a long-sought prize of metallurgy: a universal solder that can bond metals to ceramics, glass, diamonds, and, notably, the oxide materials used in semiconductor fabrication. Researchers had been hunting for such a compound for decades: the limitations of available solders have often meant electronic- and optical-device failures. After earning a PhD in materials science at Stanford University and joining Lucent Technologies’ Bell Labs in 1998,Ramirez found that mixing certain rare-earth elements, particularly lutetium, into solder metals vastly improved their bonding capabilities. Her solder is the first that can join all kinds
Of inorganic materials with high-strength bonds, and has the potential for extensive use in the electronics, optoelectronics, and microelectromechanical -systems (MEMS) industries. Ramirez also devised thin-film coatings that lessen damage caused to MEMS components by thermal expansion during operation, and she fabricated alloys that were key to Bell Labs’making a high-speed all-optical switch. Now an assistant professor of mechanical engineering at Yale University, Ramirez finds it odd that metals are “often over-looked” as a field for innovation. “These materials are fundamental,” she points out.