Atomic Scale Processing: A Key Enabler for Scalable and Coherent Quantum Technologies

Recent advances in quantum computing, including IBM’s 1000-qubit chip and imec’s 300 mm wafer transmon qubits, highlight a rapid progression towards scalable, fault-tolerant quantum systems. As quantum platforms such as superconducting and spin-based qubits evolve, the reproducibility and precision of fabrication processes have become essential. Atomic Layer Deposition (ALD) and Atomic Layer Etching (ALE) are emerging as critical tools to meet these demands. ALD’s conformal coating capabilities are particularly well-suited for developing 3D structures like through-silicon vias (TSVs), which are essential for high-density, low-loss interconnects in large-scale qubit arrays. However, transitioning ALD to 3D geometries requires careful adjustment of plasma conditions to maintain superconducting properties on vertical sidewalls. Despite these challenges, early successes with materials like TiN and NbN suggest strong potential for ALD in quantum manufacturing.

At the same time, improving surface and interface quality remains central to boosting qubit coherence times. Qubits are highly sensitive to material defects and interfacial contamination, which are known sources of decoherence. ALE’s self-limiting, smooth etching capabilities offer a superior alternative to conventional dry and wet etching by reducing surface roughness and enabling high selectivity. This process can mitigate damage and defects at key interfaces such as metal-air and substrate-air, which are critical loss points in superconducting qubits. The ability of ALE to tailor etch behaviour with high precision makes it a promising method for refining material interfaces and improving device performance. As these atomic-scale techniques continue to mature, they are poised to play a foundational role in the future scalability and reliability of quantum computing platforms.

Sources:

How atomic scale processing can help to pave the way for future quantum devices: A Workshop to bridge ALD/ALE and Quantum communities – Atomic Limits