Investigation of tantalum films growth for coplanar resonators with internal quality factors above ten million

2025/09/05 by Zikiy, E. V., Smirnov, N. S., Krivko, E. A. +12
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Quantum Physics (quant-ph)

paper · doi:10.48550/arxiv.2509.04917

Abstract

Alpha-tantalum on silicon is a promising platform for high-coherence superconducting quantum circuits. However, the growth mechanism of alpha-tantalum on silicon remains poorly understood. We present a comprehensive study on alpha-tantalum films growth on various substrate. The decisive role of a substrate material Debye temperature on phase selection mechanism in tantalum films growth is experimentally confirmed, contradicting the prior assumptions on substrate temperature influence. Crucially, we confirm that alpha-tantalum starts growing only after a 7-10 nm thick beta-tantalum underlayer. It results in ranging the critical temperature of α-Ta films from 3.77 K to 4.39 K for the total thickness from 20 to 150 nm, respectively. Finally, we compared high-quality Al and Ta coplanar resonators on silicon, demonstrating compact tantalum resonators (4/10.5/4 um) with an internal quality factor exceeding 10 million at single-photon excitation powers.

Citations

• Superconducting integrated on-demand quantum memory with microwave pulse preservation
• Reversing Hydrogen-Related Loss in α-Ta Thin Films for Quantum Device Fabrication
• High quality superconducting tantalum resonators with beta phase defects
• Mutual control of critical temperature, residual resistance ratio, stress, and roughness for sputtered Nb films
• Lumped-element two-section impedance-matched SNAIL parametric amplifier
• Mitigating Losses of Superconducting Qubits Strongly Coupled to Defect Modes
• Growth and Structure of alpha-Ta films for Quantum Circuit Integration
• Wafer-scale uniformity improvement of Dolan-bridge Josephson junction by shadow evaporation bias correction
• Grain size in low loss superconducting Ta thin films on c-axis sapphire
• Variational Quantum Algorithms
• Efficient and robust analysis of complex scattering data under noise in microwave resonators

Related

• Low-Loss Superconducting Resonators Fabricated from Tantalum Films Grown at Room Temperature
• Cryogenic growth of tantalum thin films for low-loss superconducting circuits
• Tantalum thin films sputtered on silicon and on different seed layers: material characterization and coplanar waveguide resonator performance
• Development of High-Quality α-Ta Film at Room Temperature via Seed Layer Engineering
• Growth and Structure of alpha-Ta films for Quantum Circuit Integration