Abstract
Gallium-base components can be found in a wide variety of products ranging from compact disk players to advanced military electronic warfare systems. Compared with components made of silicon, a material gallium arsenide (gaas) has replaced in some of these applications, components made of gaas can emit light, have greater resistance to radiation, and operate at faster speeds and higher temperatures. However, gaas components are more costly and more difficult to fabricate than those of silicon, so they are used only in applications where the advantage of their properties significantly outweighs their cost disadvantage. Gallium occurs in very low concentrations in the crust of the earth, and virtually all gallium is recovered as a byproduct, principally from the processing of bauxite to alumina. Most gallium applications require very high purity levels, and the metal must be refined before use until it contains no more than 1 ppm total impurities. Most gallium metal recovery and refining facilities are in Europe. Complex processing techniques are used to produce single crystals of gallium and gaas; complex techniques also are required for the fabrication of gallium and gaas optoelectronic devices and integrated circuits (ic's). Japan and the United States lead the world in gaas crystal and device fabrication. Considerable investments are being made to increase processing efficiency, develop new devices, and increase the applications of current gaas-base components.
