Scalable Diamond Quantum Microchiplets for Integrated Spin-Photon Interfaces

We present a scalable, foundry-compatible process for fabricating large arrays of diamond quantum microchiplets (QMCs) that integrate tin-vacancy color centers into nanophotonic structures. The method replaces conventional electron-beam lithography with a transferred silicon hard mask derived from a commercial semiconductor process, enabling uniform and high-throughput patterning of waveguides and photonic crystal cavities. Optical characterization confirms consistent cavity resonances and high quality factors at both room and cryogenic temperatures, demonstrating uniformity and reproducibility across large QMC arrays. Controlled gas adsorption further enables reversible tuning of cavity wavelengths and enhanced emitter-cavity coupling. This approach provides a practical and CMOS-compatible pathway for integrating scalable diamond quantum microchiplets with photonic integrated circuits, and can be extended to other wide-bandgap material platforms.