DIFFUSION OF ION-IMPLANTED SN IN SI, SI1-XGEX, AND GE

The chemical distribution of Sn ion implanted into Si, Si0.79Ge0.21, S i0.47Ge0.53, and Ge was measured with secondary ion mass spectrometry. By comparing the chemical distribution of Sn before and after high te mperature annealing, the diffusion coefficient of Sn was extracted as a function of temperature. The diffusion coefficients exhibited Arrhen ius behavior in all four cases, yielding activation energies for diffu sion of 4.91, 4.61, 3.88, and 3.05 eV, respectively, for each of the f our samples. At a given temperature the diffusion coefficient for Sn w as found to increase almost exponentially with increasing Ge content. Although the diffusion coefficient for Sn in Si and Ge is higher, rela tive to the corresponding value for self-diffusion, the activation ene rgies are similar to that for Si and Ge self-diffusion. This suggests that the diffusion mechanism for Sn is similar to that for self-diffus ion in Si and Ge and for SiGe alloys.