Determination of Diffusivities of Si Self-Diffusion and Si Self-Interstitials using Isotopically Enriched Single-or Multi-~(30)Si Epitaxial Layers

摘要

Self-diffusivity of Si has been obtained over a wide temperature range(867 deg C-1300 deg C)using highly isotopically enriched ~(30)Si epi-layers(99.88%)as a diffusion source into natural Si substrates.deg Si epi-layers were grown on both CZ-Si substrates and non-doped epi-layers grown on CZ-Si substrates using low pressure CVD with ~(30)SiH4.Diffusion was performed in resistance-heated furnaces under a pure Ar atmosphere.After annealing,the concentrations of the respective Si isotopes were measured with secondary ion mass spectroscopy(SIMS).Diffusivity of deg Si(called Si self-diffusivity,DSD)was determined using a numerical fitting process with ~(30)Si SIMS profiles.We found no major differences in self-diffusivity between bulk Si and epi-Si.Within the 867 deg C-1300 deg C range investigated,DSD can be described by an Arrhenius equation with one single activation enthalpy:DSD=14 exp(-4.37 eV/kT)cm~2/s.The present result is in good agreement with that of Bracht et.al.