Tracer diffusion of Cu in CVD β-SiC

Tracer diffusion coefficients of ⁶⁷Cu and ⁶⁴Cu in CVD β-Silicon carbide (β-SiC) have been measured in the temperature range between 623 and 1373 K by use of a serial ion-beam sputter-microsectioning technique. The temperature dependence of the diffusion coefficient D is expressed by D_Cu^* = 8 . 2_{- 0.5}^{+ 0.5} × 1 0^{- 16} exp (- 41 ± 1 kJ mol^{- 1} / RT) m² s^{- 1} . The diffusion coefficient of Cu in β-SiC is larger than those of Si and C by more than six orders of magnitude and those of Fe and Cr by one-three orders of magnitude. The activation energy for the diffusion of Cu is about one twentieth of that for the self-diffusion. The results suggest that an interstitial mechanism operates on the diffusion of Cu in β-SiC.