Preparation And Grinding Of Self-Supporting Single Crystal Diamond Film

As a prominent representative of third generation of wide-band semiconductor materials,the diamond has excellent optical,electrical,thermal,chemical inertia and other properties,and has important applications in defense,science and technology,industrial applications and other fields.The preparation of high quality single crystal diamond has always been a hot research topic,and the preparation of self-supporting single crystal diamond has very important practical significance for the application of single crystal diamond.In this paper,the preparation process of self-supporting single crystal diamond is studied emphatically,and the high quality single crystal diamond is prepared by microwave plasma chemical vapor deposition（MPCVD）method through the study of sedimentary principle,and then the self-supporting single crystal diamond film is obtained by stripping and grinding process.（1）The microscopic chemical reactions of hydrogen and methane gas on the surface of the substrate during the preparation of single crystal diamond by microwave plasma chemical vapor deposition were studied.The three growth modes of lateral growth,two-dimensional growth and three-dimensional growth were summarized.Based on this study,the effects of different growth parameters on the growth of single crystal diamond were compared.Characterization by X-ray rocking curve and Raman spectroscopy revealed that 1201 ℃ and 4.8%were the optimum substrate temperature and methane concentration,respectively.By further optimizing the parameters,high quality single crystal diamonds was prepared.（2）A detailed and in-depth analysis of the stripping process of epitaxial single crystal diamond was carried out.The epitaxial single crystal diamond film was peeled off by a highpower laser cutting machine,and the peeled surface and the side surface were completely flush,but impurities such as graphite were formed.At the same time,the ion implantationelectrochemical corrosion method was explored.The SRIM 2013 software based on the Monte Carlo calculation method thoroughly simulated the depth and discrete distribution,ion concentration and ionization energy loss of Carbon ions and Helium ions implanted into the surface of single crystal diamond.The phonon energy loss,vacancy concentration and other information,finally determined that the use of 350 keV Helium ion implantation single crystal diamond is most suitable,the implantation dose is 3×10¹⁶ ions·cm^-2.The effect of different electrolyte solutions on the corrosion rate was investigated by using the electrochemical corrosion apparatus made by ourselves.The results show that the rare HNO₃ as the electrolyte solution has the highest corrosion rate for graphite.（3）The mechanical grinding of single crystal diamond was studied.When there is reciprocating movement of the grinder,the grinding efficiency increases significantly.The surface roughness of single crystal diamond is continuously reduced by changing the grinding pressure radial feed,radial oscillation frequency and grinding direction.The results show that under the highest grinding pressure,the surface roughness is the lowest,the change of other parameters will also significantly change the surface roughness of single crystal diamond,after the atomic force microscope lest,to determine the best grinding parameters for grinding pressure 13.72 N,radial feed 28.6 mm,radial oscillation frequency 66 times·min^-1,grinding direction for[100]direction.