Characterizing Neon Thin Film Growth with an NbTiN Superconducting Resonator Array

TL;DR

This study uses superconducting resonator arrays to monitor and improve the uniformity of neon thin film growth, crucial for developing high-quality qubits based on electrons on solid neon surfaces.

Contribution

It introduces a resonator-based method for in-situ characterization of neon film growth and demonstrates how post-deposition annealing enhances film homogeneity.

Findings

Annealing reduces resonator frequency and Q factor variance, indicating improved film uniformity.

Resonator shifts correlate with film morphology, enabling real-time monitoring.

Controlled neon deposition yields repeatable film formation with measurable properties.

Abstract

Electrons levitating above the surface of solid neon have recently emerged as a promising platform for high-quality qubits. The morphology and uniformity of the neon growth in these systems is crucial for qubit performance in a scalable architecture. Here we report on the controlled growth and characterization of thin solid neon films using multiplexed superconducting microwave resonators. By monitoring changes in the resonant frequency and internal quality factor ($Q_i$) of an array of frequency multiplexed quarter-wave coplanar waveguide resonators, we quantify the spatial uniformity of the film. A pulsed gas deposition protocol near the neon triple point results in repeatable film formation, generating measurable shifts in frequency and variations in $Q_i$ across the resonator array. Notably, introducing a post-deposition anneal at 12 K for one hour improves the film homogeneity, as shown by the reduced resonator-to-resonator variance in frequency and $Q_i$, consistent with enhanced wetting. These results demonstrate resonator-based metrology as an in-situ tool for characterising neon film growth, directly supporting the development of electron on inert quantum solid qubit platforms.