V.Romanenko, G.Nikitina
Department of Physics, St.-Petersburg State University of Architecture and Civil Engineering, 4,2-nd Krasnoarmeiskaya St., 198005, St.-Petersburg, Russia. Department of Physics, St.Petersburg Technological Institute, 26 Moskovskii Ave., 198013, St.-Petersburg, Russia.
Methods for determing distribution coefficients and solubility curves based on analysis of effective distribution coefficients are examined. Examples are given for Ge-impurity, Ge-Si and InSb-GaSb systems. For Те, Pb, Sn, Sb, Se impurities in Bi, influence of current density on distribution coefficient when d.c. flows through the solid/liquid interface has been investigated. For the same case, magnetic field effect on this dependence has been studied. A method to determine the volatile impurity distribution is described.

It has been used to determine distribution coefficients of Zn, Те and Sm in GaAs. It is shown that analysis of distribution coefficients in complex systems allows to determine the chemical form in which an impurity enters the crystal matrix. The method has been used to study the behaviour of impurities in Bi2Te3. It is shown that impurities introduced into Bi2Te3 in the form of halides may partially dissociate in the melt. The phenomenon of maxima arising on concentration curves during the solidification of complex systems is described.

Analysis of that phenomenon has shown that choosing initial conditions for the crystallization of an epitaxial layer, one can control the shape of the composition distribution curve as a function of the epilayer thickness. Use of additional feeding of the liquid phase to determine the physico-chemical system parametrs has been considered. Making use of the methods developed, solubility curves of Dy, Gd and Sm in GaAs have been found. The second of proposed methods has been used for the analysis of GaAs-impurity systems. The so-called thermal arrest process is described. It allows to find the impurity distribution coefficient without measuring its concentration in the solid phase. The method has been checked for the case of In impurity in GaAs.

Дается обзор методов определения элементов диаграмм состояния и коэффициентов распределения для важнейших полупроводниковых материалов, используемых в функциональной электронике. Все методы определения основаны на использовании анализа результатов кристаллизации процессов. Приводятся примеры для систем Ge-примесь, Ge-Si и InSb-GaSb. Описано поведение примесей Те, Pb, Sn, Sb, Se в Bi при кристаллизации, сопровождаемой пропусканием постоянного тока через фронт кристаллизации. Проанализировано влияние на кристаллизацию этих же систем постоянного магнитного поля. Описан метод нахождения на концентрационных кривых кристаллизации величин коэффициентов распределения летучих примесей. Метод применен к изучению примесей Zn, Те и Sm в GaAs. На основе Bi2Te3 описано поведение при кристаллизации сложных систем. Отмечена роль химических реакций, сопровождающих в этом случае процесс кристаллизации. Объяснено появление экстремумов на концентрационных кривых при кристаллизации ряда систем с большими относительными концентрациями компонентов.