Nature of the phase responsible for the formation of SIC-type growth defects during gas-phase epitaxy of III-V compounds
The element composition and crystal structure of a second phase forming growth microdefects were investigated by electron microscopy, reflection electron diffraction, and electron-probe microanalysis at various stages of the gas-phase epitaxy of gallium and indium arsenides. Following chemical-mechanical polishing and gas etching, the elements Cu and Cr were revealed on the substrates; Cu, the element of the III group, and the doping impurity were found on the surface of the epitaxial layers. According to electron diffraction data, after chemical-mechanical polishing the substrate surface is amorphous, following gas etching and epitaxy a second phase in a polycrystalline state is found on the surface. The parameters of its structure are close to those of the basic material and of ternary compounds of the type CuGaX2 and CuInX2, where X=S, Se, Te. The possible sources of the background contamination are analyzed.