Synthesis Of CVD Diamond Films On Single-crystalline Silicon Carbide Substrate

Silicon carbide,as a new type of third generation semiconductor material,has a wide range of applications in marine sealing materials.Diamond has a series of excellent physical and chemical properties.The use of silicon carbide as a substrate for the preparation of diamond films can improve the performance of silicon carbide substrates.In this study,a DC glow discharge plasma device was used to deposit diamond thin films on the surface of single crystal silicon carbide.A diamond thin film was deposited on a single-crystalline silicon carbide substrate by comparing different process parameters such as methane concentration,substrate temperature and deposition gas pressure.The effect of various process parameters on the diamond film was studied.Deposition results were characterized by SEM,Raman,XRD,AFM and TEM.The experimental results show that the change of methane concentration will have an important influence on the grain size and crystal shape.As the concentration of methane increases from 1% to 9%,the crystallinity of the diamond film changes from(111)to(100),and finally to(111),and the grain size also gradually increases.Comparing the films deposited on the carbon/silicon terminal substrate at the same methane concentration,the denseness of the carbon terminated film is much higher,but the grain shape and size are basically the same.The deposition pressure does not affect the substrate deposition results at different terminations.The deposition of the carbon termination substrate is still higher in density than the silicon termination substrate.Films deposited on the same carbon/silicon end-substrate change the pressure of the crystal from(111)to(100)eventually to(110).As the temperature increases,the crystal form starts to have a regular square shape and becomes an irregular shape.The grain size also increases from 1 μm to 2to 3 μm.Consistent with the first two groups,the denseness of the film deposited on the carbon terminated substrate is still higher than that of the silicon termination deposition.Due to the difference in the deposition results of the carbon-silicon terminal substrate,we studied the microscopic conditions of the nucleation interface and analyzed the interaction between diamond and silicon carbide at the nucleation interface.Since the carbon terminaldoes not need to form an amorphous layer,its nucleation is more direct.Therefore,at the same time,the nucleation result of the carbon termination substrate is more moderate than that of the silicon termination substrate.Due to the poorer nucleation effect of the silicon terminal,there is a phenomenon of poor compactness and discontinuous film during film deposition.Finally,combined with the research results of the previous process parameters and the study of the nucleation results,the diamond film was deposited on the silicon carbide surface using the optimal deposition parameters.Based on the optimized parameters,conduct in-depth research.A continuous and uniform diamond film was deposited.After the XRD test,the grains were(100)oriented.At the same time,the roughness of the film reached 86.4 nm after AFM test.