Fig. 1. Mo support structure and the heat sink structure are described as follows

Fig. 2. Schematic diagram of the relative position of sample， molybdenum substrate support， heat sink and abutment

Fig. 3. Electron density distribution at a height of 16 mm （a） and simulation results showing the variation in electron density from the center to the edge of the substrate surface （b） are presented

Fig. 4. Light emission spectra associated with abutment heights of 12， 14 and 16 mm （a）， as well as the morphology of the plasma sphere at 16 mm （b）

Fig. 5. For the diamond film deposited on a ϕ50.8 mm W substrate， Raman spectra were acquired at six points spaced 5 mm apart along a radial line from center to edge （a）， and SEM images were captured at selected locations （b）~（g）

Fig. 6. For the diamond film deposited on a ϕ50.8 mm Si substrate， Raman spectra were acquired at six points spaced 5 mm apart along a radial line from center to edge （a）， and SEM images were captured at selected locations （b）~（g）

Fig. 7. For the diamond film deposited on a ϕ50.8 mm Mo substrate， Raman spectra were acquired at six points spaced 5 mm apart along a radial line from center to edge （a）， and SEM images were captured at selected locations （b）~（g）

Fig. 8. Variation diagram of the 1 331 cm^-1 peak height of diamond deposited on W， Si and Mo substrates

Fig. 9. FWHM comparison chart of diamond corresponding to six detection points from the center to the edge deposited on W， Si， and Mo substrates

Fig. 10. Relationship diagram of diamond crystal face spacing and diffraction angle sin²ψ deposited on W， Si and Mo substrates

Fig. 11. XRD patterns of deposited diamond

Fig. 12. W substrate coated with polycrystalline diamond after 200 h of deposition

Fig. 13. Raman spectra obtained from the center to the edge of a polycrystalline diamond film deposited on a W substrate over a period of 200 h

Fig. 14. TEM cross-sectional image （a）， Fourier transform （FFT） diffraction pattern （b）， and inverse FFT image （c） obtained from a selected region of the diamond film deposited on a W substrate