Frequency trimming of superconducting qubits using RF-biased ICP annealing

Abstract We propose a novel method for post-fabrication frequency trimming of superconducting qubits via RF-biased inductively coupled plasma (ICP) annealing. Junction resistance systematically increases with RF bias power, achieving a maximum increase of approximately 40% under O 2 plasma and up to 180% under Ar plasma conditions. Specifically, oxygen-based ICP annealing notably improves qubit coherence, extending both relaxation ( T 1 ) and coherence ( T 2 ) times. Transmission Electron Microscopy (TEM) analysis indicates that the observed increase in junction resistance corresponds to structural changes and barrier thickening. Our results demonstrate that RF-biased ICP annealing provides a highly effective and controllable technique to tune qubit frequencies, representing a promising pathway toward improved coherence and scalability in superconducting quantum processors.