Modeling the concentration profiles of aluminum and indium impurities in crystals of germanium–silicon solid solutions

Abstract

A one-dimensional problem of the axial distribution of Al and In impurities in uniform crystals of Ge–Si solid solutions grown by double feeding of the melt method has been solved in the Pfann approximation. The mathematical modeling results suggest that the impurity concentration profile in Ge–Si crystals of constant composition can be varied in a wide range through appropriate changes in the relationship between the crystal growth rate and the rates of feeding the melt using germanium and silicon rods. We demonstrate the possibility of growing completely homogeneous Ge–Si kAl,Inl crystals, in terms of both the concentrations of their major components and the impurity concentration profile.