Distribution of aluminum and indium impurities in crystals of Ge-Si solid solutions grown from the melt

Abstract

The problem regarding the distribution of aluminum and indium impurities in bulk crystals of solid solutions with a variable composition Ge1−x Si x (0 ≤ x ≤ 0.3) is solved in order to establish regularities of the changes in the segregation coefficients of impurities with variations in the composition of the host lattice in the germanium-silicon system. Aluminum-and indium-doped crystals of Ge1−x Si x (0 ≤ x ≤ 0.3) solid solutions with a silicon content decreasing along the crystallization axis are grown by a modified Bridgman method with the use of a silicon seed. The concentration distribution of impurities over the length of the crystals is determined from Hall measurements. It is demonstrated that the experimental data on the concentration distribution of impurities in the crystals are in good agreement with the results obtained from the theory according to which the equilibrium segregation coefficients of impurities vary linearly with a change in the composition of Ge-Si solid solution crystals.