Development of the Advanced MPE CVD System for Growth of Large Diffraction Grade Single-Crystal Diamonds with the Exceptionally Low Density of Defects

Large, diffraction grade single crystal diamond plates are needed for high power synchrotron and Free- Electron Laser (FEL) sources to enable the next generation of x-ray sources and experimentation. The current materials used cannot handle the heat loads and radiation intensity anticipated. Currently, there are no manufacturers of such material in the US. We propose the growth of high-quality single-crystal diamonds in the laboratory by chemical vapor deposition (CVD). The CVD technique does not suffer by the size limitations of other synthesis methods and can produce material with the highest purity, thermal conductivity, and radiation hardness available. Euclid Techlabs has designed a growth strategy to produce diffraction grade diamond plates with the desired material properties. In Phase 1, we have developed strategies for growing high quality, low strain, and dislocation material, which eventually can scale to larger sizes than diamond materials produced by other methods. Due to covid-19, single crystal diamond seed plates with significant areas (> 10 mm2) free of bulk defects arrived too late to properly prepare the surfaces, a critical part of the strategy. We were able to grow ca. 0.6 to 0.9 mm of epitaxial diamond on two initial plates (but not optimized to our strategy). Assessment of the quality of the epitaxial layers grown demonstrated areas as large as 1 mm2 with a very low strain-induced birefringence caused by defects implying low or no dislocations which is supported initial x-ray topography images. These results imply that we will be able to produce diffraction grade diamond by CVD.In Phase II, we will build our custom CVD reactor facility, acquire, and prepare appropriate diamond seed plates. Once the facility is operational, we will implement our growth strategy developed in Phase I for defect-free epitaxial CVD diamond single growth. To assist the development of the growth strategy, we will perform optical polarimetry, x-ray topography, x-ray rocking curve measurement, optical surface profilometry, photoluminescence, and other diagnostics as needed and appropriate. Finally, we will design and test preliminary prototype x-ray optical elements for commercialization. Enabling X-ray sources' high brightness will allow a new generation of measurements that could have a revolutionary impact across a broad area of science, including biology, medicine, cancer treatment, and quantum information.