Synthesis and characterization of boron doped diamond/β-SiC composite films

Abstract

Boron doped diamond/β-SiC composite films with a conductive diamond phase separated by the insulating β-SiC phase are fabricated by the microwave plasma chemical vapor deposition process. By manipulating the gas phase composition during the film deposition, the boron incorporation and diamond/β-SiC ratio in the composite film are well controlled. Scanning electron microscopy, transmission electron microscopy, Raman and X-ray diffraction measurements are carried out to study the structural composition of the films. It is observed that the introduction of boron during the growth process does not affect the independent growth of diamond and β-SiC crystals with high crystal quality. Scanning spreading resistance microscopy measurements confirm the presence of the conductive diamond phase and the insulating β-SiC phase in the film. The observed differences in the conductivities between diamond and β-SiC are explained by the different boron acceptor levels in diamond and β-SiC crystals. Cyclic voltammetry measurements are carried out to study the electrochemical property of the films. Our results demonstrate that boron doped diamond/β-SiC composite films are a good candidate for electroanalysis applications whereby exploiting diamond's high chemical and dimensional stability as well as its excellent electrochemical properties.