| 摘要 |
Pure single crystal forms of compounds of an element or elements from Group IIIb (Mendel</>aeef), excluding boron, with an element or elements from Group Vb, e.g. gallium arsenide and phosphide, are prepared by heating the compound with hydrogen halide vapour to a temperature sufficient to cause reaction, e.g. 135-1200 DEG C., and thereafter subjecting the resulting vaporous product to a lower temperature, e.g. 130-1195 DEG C. to condense the compound in a single crystal form. The process may be carried out either in a closed system containing the compound and hydrogen halide vapour one part of which is heated to the reaction temperature and another part maintained at a lower temperature to condense the product, or by a continuous flow method wherein the hydrogen halide vapour is passed at 2-100 c.c./min. over the compound maintained at the reaction temperature and the resulting vapour passed to a condensing zone. Pressures of 0.01-10 atmosphere are specified. The process may be used to deposit epitaxial layers of the above compounds on substrates selected from the same group of compounds and silicon and germanium. Smoother, more uniform epitaxial films are obtained when they are deposited on (100) crystal faces or (111) crystal faces where the Group V atoms are exposed. Other compounds specified are indium arsenide and phosphide and ternary compounds of the type GaAsxP1-x, GaPxN1-x, InAsxP1-x, and AlPxAs1-x, where x is greater than zero and less than one. |
