Study on mechanisms of Ar/Cl plasma etching diamonds based on hybrid MD/tfMC method and newly-developed ReaxFF parameter sets

The preparation of smooth diamond surfaces containing few dislocations is essential for the cutting edge applications such as semiconductor and quantum technologies, in which the Ar/Cl plasma processing plays a critical role. However, its atomic-scale mechanism remains unclear, primarily due to the lack of suitable ReaxFF parameter set and computational methods capable of approaching realistic timescale. In the present study, C/H/Si/Cl and C/H/Ar ReaxFF parameter sets were optimized using GARFfield, which can be used to accurately describe complex interactions between Cl/Ar plasmas and diamonds. A hybrid MD/tfMC method was employed to extend the simulation timescale, based on which the atomic level details of the Ar/Cl plasma etching were elucidated, and the etching rate (i.e., sputtering yield) was accurately predicted. Moreover, the effects of Ar/Cl plasma etching on dislocation evolution were further investigated, demonstrating that both plasma types can suppress the formation of the etch pits. This study provides a solid theoretical foundation for optimizing plasma processing to fabricate high-quality diamond semiconductor, quantum and related devices. Additionally, the newly developed parameter sets and MD/tfMC method can also be applied to address analogous challenges, such as the reactions involving Ar/Cl and other carbon-based materials.