This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: To commercialize quantum computing, manufacturers need high-quality superconducting materials for microchips, but they also require a reliable, sustainable nanofabrication process. Tantalum is a corrosion-resistant metal that meets the first criterion but not the second.
That's because it has to be deposited on a substrate at temperatures that typically exceed 400°C (752°F)—too hot for many semiconductor foundries' current tools. Cornell researchers have developed a method that uses krypton gas to slash that deposition temperature to 200°C (392°F) while depositing tantalum on silicon, a standard high-quality substrate. The process resulted in thin films that also have substantially higher electronic conductivity.
"Tantalum as a material has been shown to be very exciting from a device performance perspective, but its manufacturability had some question marks because of integration challenges such as required process temperatures," said Valla Fatemi, assistant professor and Aref and Manon Lahham Faculty Fellow in the Cornell Duffield College of Engineering, who led the project. "We figured out a relatively simple change, by using some physical and materials insights, to bring that temperature down into a zone that is translatable to nanofabrication systems in industry, while showing that in our academic context we can have leading-edge performance of these devices." The findings are published in Nature Materials. The study's lead author is postdoctoral researcher Maciej Olszewski, Ph.D. '26.
Quantum computing promises to handle faster, more complex computations by leveraging the unique quantum mechanical properties of superconductors, which carry current with little to no energy loss. The basic building blocks of the hardware are quantum bits, or qubits, which can store and process massive quantities of information. But correctly combining high-performance materials and nanofabrication techniques has proved to be one of the primary bottlenecks slowing the technology's commercial development.
Fatemi's lab explores the intersection of experimental condensed matter physics and quantum devices. Recently, his team developed characterization and nanofabrication methods to achieve high-end performance for niobium-based materials. In that work, niobium was bombarded with ions of the noble gas argon, which knocked off niobium atoms so they deposited on a substrate—a process called sputtering—forming a thin film.
"That work got the ball rolling for us in understanding a lot of the surface science and how that correlates with improving performance," Fatemi said. The researchers swapped niobium for tantalum, a transition metal with more stable surface properties and high resistance to corrosion—and a leading material for many superconducting components. But tantalum is not without challenges.
Extract — continue reading at the source.
