ISSN 10637745, Crystallography Reports, 2010, Vol. 55, No. 4, pp. 716–719. © Pleiades Publishing, Inc., 2010. Original Russian Text © G.Kh. Azhdarov, Z.M. Zeynalov, Z.A. Agamaliyev, A.I. Kyazimova, 2010, published in Kristallografiya, 2010, Vol. 55, No. 4, pp. 763–766. 716 INTRODUCTION Homogeneity is one of the main problems when growing single crystals of semiconductor solid solu tions. The Czochralski method is widely used to grow bulk semiconductor single crystals of high quality. However, the application of the conventional (conser vative) Czochralski method to binary solid solutions yields crystals of graded compositions as a result of the segregation of the component during melt crystalliza tion. There are several methods for growing homoge neous single crystals of solid solutions from the melt at a significant component segregation. Solid feeding of the melt [1] is one of the most widespread techniques. The essence of this method is that the changes in the volume and composition of the initial melt which occur during crystal growth are continuously compen sated for due to the feeding of the melt by a macro homogeneous polycrystalline ingot of specified com position. As a result, a homogeneous single crystal grows whose composition corresponds to that of the feeding rod. One significant drawback of this method is the necessity of preliminarily preparing macro homogeneous polycrystalline rods of different compo sitions. A number of difficult technological problems [2] must be solved to prepare such ingots. In addition, when the feeding rods are prepared, they inevitably absorb various residual impurities and thus become contaminated. In this paper we report the concept and theoretical basis of growing homogeneous single crystals of solid solutions by feeding the melt with ingots of its compo nents. Our purpose is to determine the process param eters and optimal conditions for growing single crys tals of semiconductor solid solutions of specified com positions by double feeding of the melt. CONCEPT AND THEORETICAL ANALYSIS The essence of our approach is shown schemati cally in Fig. 1. When a solid solution begins to grow from a melt of a specified composition, rods of the first and second components are simultaneously intro duced into the melt. Obviously, under these conditions the composition of the growing single crystal will be determined by the crystallization and melt feeding rates and the initial melt composition and volume. A mathematical description of the concentration profile of the components in the solid solution crystals grown with double feeding of the melt is presented below. The problem was solved in the Pfann approxi mation under the following standard conditions [1]: (i) the crystallization front is flat, (ii) the solid and liq uid phases are in equilibrium at the crystallization front, (iii) the diffusion of the first and second compo nents in the melt provide liquid phase homogeneity throughout the entire volume, and (iv) the diffusion of the components in the solid phase is negligible. Let us introduce the following designations: V 0 and V i are the melt volumes in the crucible at the initial and current instants, respectively; С is the total amount of the second component in the melt; and are the atomic fractions of the second component in the melt at the initial and current instants; is the atomic fraction of the second component in the crystal; is the volume of the melt crystallizing per unit time; V 1 and V 2 are the volumes of the feeding rods of the first 0 2l C 2l C 2c C c V Growth of Single Crystals of Semiconductor Solid Solutions by Double Feeding of the Melt G. Kh. Azhdarov a , Z. M. Zeynalov b , Z. A. Agamaliyev a , and A. I. Kyazimova b a Institute of Physics, National Academy of Sciences of Azerbaijan, Baku, Azerbaijan email:zangi@physics.ab.az b Ganja State University, Ganja, Azerbaijan Received December 10, 2009 Abstract—The problem of component distribution in solid solution crystals grown from a melt fed by rods made of the components of the system, with allowance for the dependence of their segregation coefficients on the melt composition, has been solved in the Pfann approximation. Examples determining the conditions for growing homogeneous single crystals of solid solutions with a specified composition and obtaining (in a unified cycle) crystals composed of several uniform parts of different compositions are presented for the Si– Ge system. The good prospects of using the method of double feeding the melt for growing single crystals of semiconductor solid solutions with specified graded and/or uniform compositions are shown. DOI: 10.1134/S1063774510040309 CRYSTAL GROWTH