Manufacturing integrated quantum systems with direct-bonded diamond membranes

Color centers in diamond are a leading platform for quantum sensing and networking technologies with many landmark experimental demonstrations. These advances can be further optimized and scaled to practical quantum systems with a diamond-based hybrid platform. Here, we developed a scalable membrane transfer technique with minimal wafer contamination and unity transfer yield. Furthermore, we demonstrate a direct-bonding method to achieve diamond-on-target-wafer stacks without any intermediate layer. The transferred membranes have nanometer-scale thickness variation over 200x200 μm² areas and high contrast color centers (measured 40-80 signal-to-background for GeV^- centers at 4 K). Moreover, the membranes are compatible with delta-doped near-surface color centers with an upward-facing growth surface after final transfer. We also demonstrate compatibility with quantum photonics, by realizing integrated nanophotonic cavities with an enhanced quality factor, and quantum biosensing, by functionalizing the membranes for bio-molecules and NV colocalization with total internal reflection (TIRF) excitation.