Related papers: Growth and Structure of alpha-Ta films for Quantum…
Quantum coherence in superconducting circuits has increased steadily over the last decades as a result of a growing understanding of the various loss mechanisms. Recently, tantalum (Ta) emerged as a promising material to address microscopic…
Superconducting films of alpha-Ta are promising candidates for the fabrication of advanced superconducting qubits. However, alpha-Ta films suffer from many growth-induced structural inadequacies that negatively affect their performance. We…
The use of $\alpha$-tantalum in superconducting circuits has enabled a considerable improvement of the coherence time of transmon qubits. The standard approach to grow $\alpha$-tantalum thin films on silicon involves heating the substrate,…
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…
Polycrystalline {\alpha}-tantalum (110) films deposited on c-plane sapphire substrate by sputtering are used in superconducting qubits nowadays. However, these films always occasionally form other structures, such as {\alpha}-tantalum (111)…
We explore the growth of {\alpha}-Ta thin films ranging from ultra-thin (2 nm) to thick (250 nm) films grown by sputter epitaxy on c-plane sapphire substrates. We utilized 100 W power with a 32 mTorr sputter pressure at 650 {\deg} substrate…
The growth of high-quality superconducting thin film on silicon substrates is essential for quantum computing, and low signal interconnects with industrial compatibility. Recently, the growth of $\alpha$-Ta (alpha-phase tantalum) thin films…
Building usefully coherent superconducting quantum processors depends on reducing losses in their constituent materials. Tantalum, like niobium, has proven utility as the primary superconducting layer within highly coherent qubits. But,…
Superconducting qubits are a promising platform for large-scale quantum computing. Besides the Josephson junction, most parts of a superconducting qubit are made of planar, patterned superconducting thin films. In the past, most qubit…
Tantalum-based transmon qubits are a promising platform for building large-scale quantum processors. So far, these qubits have been made from tantalum films grown exclusively in the alpha phase ({\alpha}-Ta). The beta phase of tantalum…
Intrigued by the discovery of the long lifetime in the {\alpha}-Ta/Al2O3-based Transmon qubit, researchers recently found {\alpha}-Ta film is a promising platform for fabricating multi-qubits with long coherence time. To meet the…
Tantalum thin films sputtered on unheated silicon substrates are characterized with microwaves at around 10 GHz in a 10 mK environment. We show that the phase of tantalum with a body-centered cubic lattice ($\alpha$-Ta) can be grown…
Two single crystal phases of tantalum nitride were stabilized on c-plane sapphire using molecular beam epitaxy. The phases were identified to be $\delta$-TaN with a rocksalt cubic structure and $\gamma$-Ta$_2$N with a hexagonal structure.…
Developing new material platforms for use in superconductor-semiconductor hybrid structures is desirable due to limitations caused by intrinsic microwave losses present in commonly used III/V material systems. With the recent reports on…
Utilizing tantalum (Ta) in superconducting circuits has led to significant improvements, such as high qubit lifetimes and quality factors in both qubits and resonators, underscoring the importance of material optimization in quantum device…
Realization of practical superconducting quantum computing requires many qubits of long coherence time. Compared to the commonly used Ta deposited on c-plane sapphire, which occasionally form {\alpha}-Ta (111) grains and \b{eta}-tantalum…
Motivated by recent advancements highlighting Ta as a promising material in low-loss superconducting circuits and showing long coherence times in superconducting qubits, we have explored the effect of cryogenic temperatures on the growth of…
The unique property of tantalum (Ta), particularly its long coherent lifetime in superconducting qubits and its exceptional resistance to both acid and alkali, makes it promising for superconducting quantum processors. It is a notable…
Over the past decades, superconducting qubits have emerged as one of the leading hardware platforms for realizing a quantum processor. Consequently, researchers have made significant effort to understand the loss channels that limit the…
Superconducting qubits based on tantalum (Ta) thin films have demonstrated the highest-performing microwave resonators and qubits. This makes Ta an attractive material for superconducting quantum computing applications, but, so far, direct…