Low-Temperature Plasma Synthesis of Cubic Boron Nitride
POSTER
Abstract
Low-temperature plasma synthesis of cubic boron nitride (cBN) coatings on diamond seeded silicon substrates was carried out in a microwave plasma chemical vapor deposition (MPCVD). Low-temperature plasmas (LTP) are severely non-equilibrium systems that use free electrons to create a novel physical and chemical environment at low gas temperatures. In MPCVD, hydrogen (H2), argon (Ar), a mixture of diborane in H2 (95% H2, 5% B2H6), and nitrogen (N2) were used as the feed gas. A direct current (DC) bias system was used to externally bias the sample negatively where the MPCVD chamber wall was grounded. The presence of sp3 bonded BN in the synthesized coatings was demonstrated by X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR). The cBN content in the coating increases with increasing Ar flow, reaching a maximum at the maximum Ar flow of 400 sccm used in this study. High-resolution XPS scans for B1s and N1s indicate that the deposited coating contains more than 70% cBN. The surface roughness of the BN coatings was also measured using Atomic Force Microscopy (AFM). This study found that energetic argon ions generated in microwave-induced plasma are beneficial for cBN formation in MPCVD.
*This work was supported by the National Science Foundation (NSF) EPSCoR RII-Track-1 Cooperative Agreement No. OIA-1655280. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation. The author acknowledges financial support from the Alabama Graduate Research Scholars Program (GRSP) funded through the Alabama Commission for Higher Education and administered by the Alabama EPSCoR.
Publication:1. Kallol Chakrabarty, Paul A Baker, Vineeth M Vijayan, Shane A Catledge, Effect of argon flow rate and direct current bias on the growth of boron nitride coating in low-temperature plasma, AIP Advance 12(8):085228, 2022, https://doi.org/10.1063/5.0102036. 2. Kallol Chakrabarty, Paul A. Baker, Vineeth M. Vijayan, Shane A. Catledge, Bias enhanced formation of multiphase superhard boron nitride coating in microwave plasma chemical vapor deposition, Materials; 14(23):7167, 2021, https://doi.org/10.3390/ma14237167.
