OXYGEN EQUILIBRIUM BETWEEN GERMANIUM AND GAS OVER MELT DURING GROWTH

The equilibrium relationship between the oxygen content of germanium grown from the melt and the PH20/PH2 ratio during growth has been calculated using published data for oxygen solubility in germanium and for GeO2(s) reactions where [O(s)] is in atoms per cm3. Substantial agreement is reported between this expression and the oxygen concentrations of several Czochralski crystals where ph2o/ph2 of the furnace effluent was determined during growth. The oxygen concentrations reported cover the range [O(s)] = 1012-1015 cm-3 and were measured by the lithium precipitation method. By implication oxygen in the melt also must be in equilibrium with PH20/PH2 during growth. Using the chemical potential of oxygen thus deduced, the conditions for the stability of Al2O3(s) and B2O3(l) in the melt are calculated. © 1979, The Electrochemical Society, Inc. All rights reserved.