Ultrahigh vacuum packaging and surface cleaning for quantum devices

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 T2134 mu s after vacuum-loading these samples into a bottom loading dilution refrigerator in the UHV-package.

Automated summary

An ultra-high vacuum (UHV) package for superconducting qubit chips or other surface sensitive quantum devices is described, including the loading procedure, treatment capabilities, and measurement results. The package retains vacuum during transfer to cryogenic temperatures and has been shown to improve the performance of flux tunable qubits.