An Analysis for Si Contamination in GaP

Chemical transport of solid using as reactant often results in the formation of a voluminous residue conforming to the shape of the initial charge. Analysis by x‐ray fluorescence showed such residues to consist primarily of silicon, probably as . It was shown that the transport reaction did not introduce extraneous from vapor phase reactions with the quartz liner. In addition it was demonstrated that silicon dissolved in gallium could be almost completely recovered as a residue. Thermodynamic considerations are presented to show that unintentional or deliberate moisture contamination of the reactants is required to prevent losses. The method is proposed as a quantitative tool for determination of Si content in Ga, , and with a sensitivity of . It was applied to analyze polycrystalline and single crystals of grown from this material by the Liquid Encapsulated Czochralski (LEC) technique. The analysis confirmed that Si doping of the LEC crystals by the quartz crucibles does not occur and undoped LEC crystals normally contain less than . Moreover, most of the Si contained in Si‐doped melts is "gettered" by the encapsulant, probably through oxidation.