Influence of boron doping on growth characteristic of diamond films prepared by hot cathode DC chemical vapor deposition

Boron-doped diamond films were prepared by hot cathode DC chemical vapor deposition system with B(OCH₃)₃ as dopant. The influence of boron doping on growth characteristic of diamond films was investigated by plasma optical emission spectroscope, scanning electron microscope (SEM), Raman spectroscope, and X-ray diffraction (XRD). Comparing with the growth process for undoped diamond films, it is found that stable glow discharge can sustain for a long time at low boron doping concentration in hot cathode DC chemical vapor deposition system. The species of glow plasma radicals (H_α, H_β, C₂, CH) do not change after boron doping, while the concentration of C₂ radical increases and the concentration of CH radical decreases. The growth rate of boron-doped diamond film increases to 0.65 mg·cm^-2·h^-1. The boron-doped diamond films possess well-faceted polycrystalline diamond with (111) dominant orientation, and the quality of boron-doped diamond films is improved in comparison with that of undoped diamond films. Boron atoms in the films are located at the substitutional site or interstitial site in diamond lattice, which do not destroy the diamond crystalline structure.