High-temperature annealing effects on epitaxial TiN films on 4H-SiC

To gain deeper insights into the impact of very high-temperature annealing on TiN film quality and thermal diffusion phenomena, the deposited TiN films underwent annealing in an induction heating furnace across a temperature range from 1150 degrees C to 1700 degrees C. Our findings indicate that TiN films remain stable, and the fullwidth at half-maximum (FWHM) of TiN (111) noticeably reduced by about 30 % when annealed at 1250 degrees C. However, as the annealing temperature rises to 1400 degrees C, the film composition gradually enriches with carbon as TiC x N 1- x with x up to 0.5. After annealing at 1700 degrees C, the film is further enriched with x larger than 0.5. For a long time annealing at 1700 degrees C, the decomposition of SiC substrate with void formation is verified from observations by cross-sectional transmission electron microscopy.