800 kHz Femtosecond Laser Cleaning of Microwave Plasma Chemical Vapor Deposition Diamond Growth Substrate

Microwave Plasma Chemical Vapor Deposition (MPCVD) plays a crucial role in the growth of high-quality diamonds. However, during the MPCVD process, residues such as polycrystalline diamond, and graphite often adhere to the high-temperature growth substrate surfaces, potentially degrading diamond growth quality. To effectively remove these contaminants and improve the quality of diamond growth, this study employed an 800 kHz femtosecond laser to clean growth substrates with residual deposits. We assessed the effects of multiple cleaning cycles on residue removal from the Foundation Trench Region (FTR) and Inwall Region (IR) and on substrate quality. The results indicate that multiple scans at a laser power of 2.38 W, a repetition rate of 800 kHz, a scanning speed of 1800 mm/s, and a scan spacing of 10 μm significantly removed residues, reduced substrate surface roughness, and restored substrate cleanliness. This approach enhances the quality and efficiency of diamond growth via MPCVD. The application of high-repetition-rate femtosecond laser cleaning techniques for growth substrates significantly improves the quality of regenerated diamond films, providing crucial support for the preparation of high-quality diamond materials.