Apparatus and method for growing semiconductor crystal

Abstract

The present invention relates to molecr beam epitaxy, in particular, to a gas source molecular beam epitaxy apparatus using compound gases as sources of semiconductor component elements, and also relates to a method for growing semiconductor crystal using this apparatus. It is an object of the present invention to prevent an epitaxial layer from being contaminated with organic compounds produced by decomposition of source gases. It is another object to grow a high purity semiconductor crystal at a growth rate high enough for practical applications. To achieve the above objects, in a growth apparatus in accordance with the present invention, the ambient gas pressure is maintained at the order of 10.sup.-5 -10.sup.-3 Torr during a growing process. The distance between a substrate on which semiconductor is to be grown and a gas effusion cell made shorter than the mean free path of source gases and by-products produced by decomposition of the source gases, wherein the mean free path is determined from the above ambient gas pressure. Moreover, a heat insulation plate is provided between the gas effusion cell and the substrate, wherein the heat insulation plate has apertures corresponding to gas effusion cells. Furthermore, as source gases, amino compounds are used such as trimethyl amine galane ((CH.sub.3).sub.3 N.multidot.GaH.sub.3), triethyl amine alane ((C.sub.2 H.sub.5).sub.3 N), tris-dimethylamino arsine (As(N(CH.sub.3).sub.2).sub.3), trimethyl amine ilane ((CH.sub.3).sub.3 N.multidot.InH.sub.3), and tris-diethylamino phosphine (P(N(C.sub.2 H.sub.5).sub.2).sub.3), wherein the amino compounds include elements composing compound semiconductor such as GaAs and InP.