Superconducting Diamond for Quantum Applications: CVD Diamond Doping Control and Characterization

Diamond-based technology has been found to have exceptional robustness and performance in quantum and thermal applications, including but not limited to superconducting devices such as SQUIDs (Superconducting Quantum Interference Devices), Josephson junctions for superconducting qubits, and high-power electronics. Diamond, in its purest form, is an electrical insulator; however, by doping the material with elements such as boron, the electrical properties of the diamond alter to form a p-type semiconductor and even a superconductor at cryogenic temperatures. Doping is achieved through fabrication processes such as Microwave Plasma Chemical Vapor Deposition (MPCVD) or Hot Filament CVD (HFCVD), offering reliable production of boron-doped diamond (BDD). This study focuses on the controlled doping of diamond with boron and its structural and electronic characterization through Raman Spectroscopy and Scanning Electron Microscopy (SEM). Samples with varying doping concentrations are further characterized through electrical measurements, including analysis of superconducting transition temperatures. The results of this study aim to serve as a benchmark for repeatability and scalability, and provide clarity for reliably fabricating superconducting BDD films, supporting future diamond-based quantum technology.