UNIVERSITY PARK, Pa. — Riccardo Torsi, a doctoral student studying materials science and engineering in Penn State’s College of Earth and Mineral Sciences, received a 2019 National Science Foundation Graduate Research Fellowship to investigate improving microelectronics. He is one of seven EMS students and 24 Penn State students to receive the honor.

Torsi is investigating interconnects, which connect different elements in integrated circuits. In electronic circuits, copper serves as a conductor and its atoms can diffuse, or spread out, from their source and corrupt surrounding materials. Devices called diffusion barriers are placed between the copper and the adjacent material to address this, said Torsi, but these diffusion barriers can be difficult to scale down for manufacturing.

That’s where molybdenum disulfide comes in.

This material is theoretically viable for use as a nanometer-thick diffusion barrier, which could allow for improved microelectronics. For comparison, a human hair is roughly 75,000 nanometers in width.

But synthesizing the material can be difficult, Torsi said.

“It’s a great engineering challenge to grow high-quality molybdenum disulfide,” Torsi said. “It’s typically grown at high temperatures, and that’s not an option for use in this technology.” 

Torsi also is investigating doping, or introducing an impurity into the material, to improve the conductivity of the diffusion barriers and thereby enhance their performance. He hopes to gain a more thorough understanding of the mechanisms underlying the doping process and explore novel techniques, such as a laser-assisted method.

Torsi chose to apply for the fellowship after enrolling in MATSE 597, a special topics class taught by Joshua Robinson, associate professor of materials science and engineering, on proposal writing. Two other students who had taken the class, Katy Gerace and Timothy Bowen, also received NSF fellowships.

“Riccardo is a top materials science student, and his award reflects his potential as a future scientific leader,” said Robinson, who serves as Torsi’s adviser. “I am excited to have him as part of our academic family.”

Torsi said he chose to attend Penn State for its impressive laboratory facilities and research opportunities.

“Receiving this award was huge for me, because it supports my goal to become a researcher,” said Torsi, who hopes to work at a national lab in quantum materials research. 

The NSF Graduate Research Fellowship Program recognizes and supports outstanding graduate students in NSF-supported science, technology, engineering and mathematics disciplines who are pursuing research-based master’s and doctoral degrees at accredited institutions in the United States. About 12,000 students apply annually and 2,000 receive awards.