Abstract
Diffusion of tin into Si from tin-doped oxide is studied by the backscattering and channeling analyses. The depth distribution of tin in Si can be fitted to complementary error functions. The diffusion coefficient can be expressed as D=0.054exp (-3.5eV/kT). The solubility limit in Si and the segregation constant between Si and SiO2 are estimated to be 6∼8×1019/cm3 and 0.066 at 1100°C∼1200°C, respectively. The lattice location of tin in Si is also determined by angular scan, and it is found that more than 90% of tin atoms occupy substitutional sites. Uniformity of the concentration over a silicon wafer is also checked with the microanalysis system by using backscattering and is found to be good. Effect of post-diffusion of phosphorous or boron on the depth profile of tin is also studied.