Vapor-phase growth of epitaxial crystals.

摘要

To grow crystals epitaxially, carriergas is bubbled through a trialkyl gallium (3) and the vapors are carried to a reactor (7) in amount of the trialkyl gallium being 10<-><3>to 10<-><5>mol/min; arsenic trihydride (4) having a volatile impurity content of not more then 1.5 mol ppb on a germanium tetrahydrate conversion is introduced into the reactor through a flow controller (6) at an amount of 5 to 200 times that of the gallium material and the gaseous mixture is heat decomposed by a heater (9) in the vicinity of a substrate (11) to cause growth of a GaAs epitaxial crystal. Crystals of other semiconductive compounds of Groups III, IV, and V can be grown similarly by replacement of the arsonic, eg. by aluminium or indium in place of gallium or phosphine or stibine in place of the arsine. Suitable alkyls are methyl, ethyl or butyl. The effect of impurities and residual electron concentration is described. The crystals prepared have a buffer of a high resistance GaAs or AlxGa1-xAs epitaxial crystal, where 0 2 x 10<1><4>/cm arising from the arsine, and may have also such an N-type crystal layer; they are useful in field effect transistors.