Diamond Quantum Microchiplets Advance Scalable Photonics Manufacturing with Foundry Precision

Researchers are tackling the significant challenge of scaling up quantum technologies for secure networks and advanced computing. Jawaher Almutlaq, Alessandro Buzzi, and colleagues from the Research Laboratory of Electronics at MIT, alongside collaborators from King Abdullah University of Science and Technology, PhotonFoundries, Inc, and The MITRE Corporation, present a novel manufacturing approach to diamond photonics. They demonstrate a method utilising commercial semiconductor foundries to pattern silicon masks and transfer them onto diamond, enabling the creation of large arrays of nanoscale optical structures. This foundry-enabled process bypasses slow, bespoke fabrication techniques, improving device uniformity, yield and throughput, and paving the way for scalable, high-quality diamond microchiplets integrated with existing photonic and electronic circuits.

Silicon masks enable diamond quantum device fabrication

Scientists have developed a new manufacturing approach to advance diamond quantum photonics towards industrial production. The research addresses a major challenge in scaling up the creation of Secure networks and powerful information processing systems reliant on diamond-based devices. Instead of directly patterning nanoscale structures onto diamond, which is a slow and difficult process, the team fabricated high-precision silicon masks using commercial semiconductor foundries. These masks were then transferred onto diamond via microtransfer printing, effectively shifting the most demanding pattern-definition steps away from the delicate diamond substrate and significantly improving uniformity, yield, and throughput.
This innovative method enabled the creation of hundreds of diamond “quantum microchiplets” exhibiting enhanced optical performance and controlled interaction with Quantum emitters. The chiplet format is particularly advantageous as it allows for the replacement of defective devices and facilitates seamless integration with existing photonic and electronic circuits. Experiments demonstrate that high-quality diamond devices can now be produced using scalable, foundry-compatible techniques, representing a substantial leap forward in the field. This approach establishes a practical pathway for building large-scale photonic systems and hybrid quantum-classical technologies leveraging established semiconductor manufacturing infrastructure.

The team’s work centres on utilising diamond, an attractive material for quantum devices due to its ability to host atomic-scale defects that emit single photons and maintain information stability. Embedding these emitters within diamond nanophotonic structures, such as waveguides and optical cavities, enhances photon extraction and enables deterministic spin, photon interfaces, crucial for scalable quantum architectures. While previous attempts at fabricating these structures relied heavily on electron-beam lithography directly on diamond, limiting scalability, this study introduces a wafer-scale approach based on foundry-fabricated silicon hard masks. Specifically, the researchers demonstrate a process where high-resolution patterns are defined on silicon wafers in a commercial foundry, then transferred to diamond using microtransfer printing. This technique resulted in statistically uniform arrays of improved-Q diamond nanophotonic cavities with verified coupling to solid-state quantum emitters, with cavity quality factors improved by approximately 3, 8× relative to prior fabrication and heterogeneous integration demonstrations. By performing lithography on silicon instead of diamond, the team achieved parallel and reproducible fabrication, paving the way for large-scale integration of quantum photonic systems with both photonic integrated circuits and CMOS platforms.

Silicon Mask Transfer for Diamond Photonics enables advanced

Scientists developed a novel manufacturing approach to advance diamond photonics towards industrial production. Instead of directly patterning diamond with lithography, the research team fabricated high-precision silicon masks utilising commercial semiconductor foundries. These masks were then transferred onto diamond substrates via microtransfer printing, defining large arrays of nanoscale optical structures and circumventing the limitations of direct diamond patterning. This innovative technique shifts the most demanding pattern-definition steps away from the fragile diamond material, substantially improving uniformity, yield, and throughput during device fabrication.

The study pioneered a chiplet-based methodology, fabricating hundreds of diamond “quantum microchiplets” with enhanced optical performance and precise control over interactions with quantum emitters. Researchers engineered the process to create suspended diamond structures, enabling efficient light confinement and manipulation at the nanoscale. This approach allows for the replacement of defective chiplets and facilitates seamless integration with existing photonic and electronic circuits, offering a modular and scalable platform for quantum photonic systems. The team demonstrated cavity quality factors improved by approximately 3, 8× relative to prior fabrication and heterogeneous integration demonstrations.

Experiments employed a detailed fabrication workflow beginning with quantum microchiplet and mask design, followed by foundry mask fabrication. Subsequently, the silicon hard mask was microtransfer printed onto single-crystal diamond, and reactive-ion etching was used to define the quantum microchiplets. This process leverages the precision of commercial semiconductor foundries to create intricate nanoscale patterns with high fidelity. The system delivers wafer-scale fabrication of silicon hard masks, enabling parallel and reproducible device creation without the need for direct lithography on the diamond substrate. This method achieves high-quality diamond quantum devices using scalable, foundry-compatible techniques, representing a practical pathway towards large-scale quantum photonic systems and hybrid quantum-classical technologies. The resulting chiplet platform preserves post-fabrication selection and compatibility with established photonic integrated circuit and CMOS integration schemes, unlocking new possibilities for complex quantum circuits and devices.

Silicon masks enable diamond quantum microchiplet fabrication

Scientists have developed a new manufacturing approach for diamond photonics, bringing it closer to industrial production. Instead of directly patterning diamond with lithography, the team fabricated high-precision silicon masks using commercial semiconductor foundries and transferred them onto diamond via microtransfer printing. This innovative method shifts the most demanding pattern-definition steps away from the delicate diamond substrate, significantly improving uniformity, yield, and throughput during device fabrication. Experiments revealed the successful creation of hundreds of diamond “quantum microchiplets” exhibiting enhanced optical performance and controlled interaction with quantum emitters.

The research demonstrates the production of wafer-scale arrays of diamond nanophotonic structures using this foundry-compatible technique. Measurements confirm that the silicon hard masks, fabricated using commercial lithography, enable parallel and reproducible fabrication without any direct lithography performed on the diamond itself. The team achieved high-yield transfer of large-area suspended membranes, measuring 750μm x 750μm, using commercial micro-transfer printing. Results show statistically uniform arrays of improved-Q diamond nanophotonic cavities, with verified coupling to solid-state quantum emitters, representing a substantial advancement in device fabrication.

Tests prove that this approach delivers cavity quality factors improved by approximately 3, 8× relative to prior fabrication and heterogeneous integration demonstrations. The chiplet format allows for the replacement of defective devices and facilitates integration with existing photonic and electronic circuits, offering a modular and flexible platform. Specifically, the design incorporates photonic crystal cavities embedded in 300-nanometer-wide nanobeam waveguides, patterned with 127-nanometer air holes optimized for coupling to Sn-117 color centers. This breakthrough delivers a practical pathway toward large-scale quantum photonic systems and hybrid quantum-classical technologies built on established semiconductor manufacturing infrastructure. The work demonstrates wafer-scale enabled fabrication of silicon hard masks, high-yield transfer of large-area membranes, and statistically uniform arrays of improved-Q diamond nanophotonic cavities, all crucial for advancing quantum technologies. Measurements confirm the viability of this scalable approach for producing high-quality diamond quantum devices, paving the way for future advancements in secure networks and powerful information processing.