X-Ray Diffraction Studies of the Influence of Substitutional Carbon on Si/Ge Interdiffusion in SiGe/Si Superlattices

摘要

We show that substitutional C enhances interdiffusion in SiGe heterostructures. Si/Ge interdiffusion was studied in SiGe(C)/Si(C) superlattice structures with different positions and concentrations of substitutioal carbon in the temperature range 700 °C - 950 °C for Ge (about 20%) and carbon (0-0.5%) concentrations, which are relevant for SiGe(C) device applications. The observed enhanced diffusion of Ge by substitutional C is attributed to a perturbation of Si point defect densities due to outdiffusion of C from regions of high C concentration.