The preparation of semiconductor materials by epitaxial deposition has rapidly gained prominence in recent years. GaAs(1-x)Px alloys of variable composition, deposited on GaAs substrates, have been prepared in an open-tube reactor using H2, AsCl3, and PCl3 with GaAs source material, The deposits ranged in composition from GaAs to GaAs0.5P0.5 and were 10-30 microns thick.
X-ray diffraction topography was employed to evaluate the structural perfection of the monocrystalline GaAs substrates and the perfection of the deposited Ga(As, P) films. A scanning-reflection technique was developed to study the concentration, type, and spatial distribution of imperfections over large areas (∼8 cm2) to depths of 25 microns. Some areas of investigation included (1) the poly cry stallinity of some deposits, (2) the effect of substrate perfection on the film quality, (3) the depth of mechanically induced damage, and (4) the structural perfection of magnesium-diffused GaAs and Ga(As, P).