Cornell Cuts Tantalum Qubit Deposition Temperature in Half Using Krypton Gas

A Cornell team led by Valla Fatemi published in Nature Materials a krypton-gas sputtering method for depositing tantalum thin films on silicon at 200°C, roughly half the temperature (400°C+) previously required. The lower-temperature process stabilizes the desired crystal phase, substantially raises the film's electronic conductivity, and yields superconducting qubits of markedly higher quality, all while staying compatible with standard back-end-of-line semiconductor fabrication tools — easing a key manufacturing bottleneck for scaling tantalum-based superconducting quantum processors.