Ultrahigh Vacuum Packaging and Surface Cleaning for Quantum Devices

Abstract

We describe design, implementation and performance of an ultra-high vacuum (UHV) package for superconducting qubit chips or other surface sensitive quantum devices. The UHV loading procedure allows for annealing, ultra-violet light irradiation, ion milling and surface passivation of quantum devices before sealing them into a measurement package. The package retains vacuum during the transfer to cryogenic temperatures by active pumping with a titanium getter layer. We characterize the treatment capabilities of the system and present measurements of flux tunable qubits with an average T${}_1=84\mu$s and T${}_2^{echo}=134\mu$s after vacuum-loading these samples into a bottom loading dilution refrigerator in the UHV-package.

5 pages, 6 figures