Reaction of Ta Thin Film with Single Crystalline (001) Beta-SiC

摘要

The reaction between a sputter-deposited Ta film (320 nm thick) and a singlecrystalline (001) P-SiC substrate induced by vacuum annealing at temperatures of 600-1200 CC for 1 h (30 min at 1100 0C) a) is investigated by 3 MeV He+ + backscattering spectrometry, x-ray diffraction, secondary ion mass a) spectrometry, and transmission and scanning electron microscopies. No significant reaction is observed at 800 CC or at lower temperatures. At 900 CC, the main product phases are Ta2C and carbon-stabilized Ta5Si3. A minor amount of unreacted Ta is also present. After annealing at 1000 CC, all the tantalum has reacted; the reaction zone possesses a multilayered structure of p-SiC/TaC/carbon-stabilized Ta5Si3/Ta5Si3,Ta2C. The diffusion path at 1000 CC is plotted on the isothermal section of the Ta-Si-C phase diagram. At 1100 0C, the reacted layer has an interface with the SiC substrate that is still quite flat but has a rough surface due to the formation of macroscopic voids within the reacted layer. The equilibrium products predicted by the phase diagram are TaC and TaSi2. This final state is reached by annealing at 1200 0C for 1 h. At that point, the reacted layer has a laterally very uneven structure and morphology.