Purification of solid epitaxial deposition sources - by dissolution in metal melt and resolidification on melt surface

摘要

Solid source of a material (pref. AIIBV cpd.) ofr epitaxial deposition from the gas phase is purified by placing it in the lower part of a refractory vessel horizontally partitioned with a glass frit diaphragm (pref. quartz glass) and introducing into the upper part of the vessel a solvent for AIIIBV, liquid at the operating temp. (pref. 800 degrees C), which has a greater s.g. than AIIIBV (pref. molten AIII is used as a solvent). the solvent penetrates through the diaphragm into the lower part of the vessel; AIIIBV dissolves in it and diffuses upwards ultimately forming a solid layer of pure AIIIBV on the surface of the molten AIII, which constitutes a pure source for gas-phase epitaxial deposition as most of the impurities remain in the molten AIII. The operation is carried out under pure H2. the pref. AIIIBV cpds. are GaAs and GaP (solvent Ga), InP or InSb (solvent In).