June 27, 2011
Four Drexel University College of Engineering professors are part of a group of researchers who will share a $2.2 million grant from the Office of Naval Research to develop new electronic devices.
Drexel Professors Steven May, James Rondinelli, Jonathan Spanier and Mitra Taheri from the Department of Materials Science and Engineering are joined by Professor Andrew Rappe of the University of Pennsylvania’s Chemistry Department. Drexel will receive $1.75 million of the funding for the four-year project, which began this summer.
The group’s research is aimed at developing a new type of transistor, or a universal on/off switch used by many of today’s electronic devices such as smart phones and laptops. Current transistor technology, using silicon as a base, is limited because engineers’ ability to shrink the size of the component appears to be reaching a threshold.
“Silicon-based transistors are reaching their scaling limitations,” said Rondinelli. “This has very real consequences on the performance – not only the speed, but also the power consumption of our portable gadgets.”
Drexel’s team of materials scientists is working to develop the use of substances called “complex metal oxides,” which may take the place of silicon in transistors. Simple metal oxides, such as oxidized iron or rust, are common in nature. Complex metal oxides consist of two or more earth-abundant metals, calcium and iron for example, as opposed to just one element, which combine with oxygen to form a stable compound.
The presence of more than one metal in the crystal enables these materials to display diverse electronic states. They can be magnetic insulators, metals or superconductors. This additional flexibility provided by the use of complex metal oxides could allow engineers to create a transistor that requires less power and switches on and off at speeds much faster than current silicon transistors.
“The silicon miniaturization roadblock is in part why laptop computers run so hot,” Rondinelli said. “Because many consumers are demanding better performance and efficiency out of their mobile devices, the semiconductor industry is looking toward next generation transistor materials.”
According to the group, processing speeds well beyond terahertz (THz) could be possible using the new technology. Complex oxide materials are compatible with existing technologies. Simple oxides, precursors to complex oxides, are already in use in microprocessors, which could open the door for complex oxide transistors as the wave of the future.