Diffusion of ion implanted Sn in Si, Si_1-xGe_x, and Ge

The chemical distribution of Sn ion implanted into Si, Si _0.79Ge_0.21, Si_0.47Ge_0.53, and Ge was measured with secondary ion mass spectrometry. By comparing the chemical distribution of Sn before and after high temperature annealing, the diffusion coefficient of Sn was extracted as a function of temperature. The diffusion coefficients exhibited Arrhenius behavior in all four cases, yielding activation energies for diffusion of 4.91, 4.61, 3.88, and 3.05 eV, respectively, for each of the four samples. At a given temperature the diffusion coefficient for Sn was found to increase almost exponentially with increasing Ge content. Although the diffusion coefficient for Sn in Si and Ge is higher, relative to the corresponding value for self-diffusion, the activation energies are similar to that for Si and Ge self-diffusion. This suggests that the diffusion mechanism for Sn is similar to that for self-diffusion in Si and Ge and for SiGe alloys.