Physical vapor deposition reactor design and validation for in-space manufacturing of aluminum nitride single crystals

AlN is an emerging wide bandgap semiconductor with significant potential to outperform silicon carbide (SiC) and gallium nitride (GaN) in power electronics and optoelectronics. However, current terrestrial production faces major challenges, including high dislocation densities, point defects, and limitations in wafer size. To enable large-scale commercial adoption, AlN substrates must achieve a 10-100x reduction in dislocations, improved point defect control, and increased wafer diameter. Microgravity offers a unique environment to overcome these barriers by: 1. Ensuring Uniform Mass Flux – Eliminating thermally driven convection stabilizes the crystal growth front, reducing defects. 2. Controlling Thermal Gradients – Microgravity minimizes stress-induced defects, improving crystal uniformity and scalability. 3. Accelerating Seed Development – Producing ultra-high purity seeds in space can significantly shorten the decades-long terrestrial improvement cycle, advancing wafer quality by generations within months. Building on Phase I progress, the Phase II project aims to develop a flight-ready prototype of the PVD reactor for AlN crystal growth aboard the ISS. The reactor will also support additional high-temperature material research, such as silicon carbide and oxide crystals, with potential future applications on Axiom Space’s commercial LEO platform. The key objectives of Phase II include: 1. Refining Reactor Design – Modifying the reactor to meet ISS middeck locker size requirements and integrating all system components. 2. Optimizing AlN Growth – Conducting system modeling and empirical testing to refine the crystal growth process. 3. Safety & Mission Integration – Completing NASA’s Phase I Safety Review, securing payload integration approval, and preparing for deployment. By leveraging space-based manufacturing, this project aims to revolutionize AlN production, positioning the U.S. as a global leader in next-generation semiconductor technology.