Atomic Layer Smoothing for Quantum Materials: An Initial Investigation

In the realm of quantum devices such as qubits and microwave kinetic inductance detectors, surface imperfections in metallic and dielectric films have been identified as a root cause of non-ideal behaviors. Despite significant investigations into surface-induced decoherence and low-frequency fluctuations, current nanofabrication techniques remain inadequate in addressing these issues. We introduce a novel surface smoothing technique utilizing a 'reversal' mechanism in atomic layer deposition (ALD), specifically isotropic plasma atomic layer etching (ALE), to mitigate Angstrom-level defects in quantum materials. Our approach focuses on minimizing surface roughness and native oxides, thereby enhancing device performance. This talk provides insights into the application of atomic layer smoothing in the processing of aluminum nitride, with observed smoothing effects at the Angstrom scale, offering potential improvements to AlN-based quantum optical devices. Further discussion will cover advancements in ALE for metallic aluminum, a material frequently used in superconducting circuits. We propose an integrated ALE-ALD approach to achieve smoother and oxygen-free surfaces.