X-Ray absorption study of the bonding structure of BCN compounds enriched in carbon by CH4 ion assistance

Ternary BCN compounds can be grown by B4C evaporation and concurrent N2/Ar ion assistance in both hexagonal and cubic structures, depending on the deposition parameters. However, the films are always carbon poor, with a maximum carbon content of approximately 10 at.% in hexagonal BCN, and 5 at.% of C in cubic BCN. In order to increase the carbon content in the films, we have added CH4 to the bombarding gas mixture. In the case of hexagonal structures, the additional carbon atoms are efficiently incorporated to the h-BCN without finding a solubility limit. For the cubic structures, the carbon enrichment induces a disruption of the structure and segregation into h-BCN and BxC domains.