INITIAL-STAGES OF EPITAXIAL-GROWTH OF GAP ON SI WITH ASH3 PREFLOW

A previous paper reported that when GaP epilayers are grown on Si substrates, an As-stabilized surface made by AsH3preflow before growth prevents many defects from generating at the GaP/Si interface, and that consequently, the crystalline quality of GaP epilayers is markedly improved. This letter describes the AsH3preflow effect on the initial stages of GaP epitaxial growth. The relative ease with which As or P atoms are absorbed onto Si surfaces is observed using X-ray photoelectron spectroscopy. Although preflow before GaP growth causes As or P atoms to absorb onto Si surfaces, As atoms are absorbed more easily than P atoms. The initial stages of GaP epitaxial growth on Si substrates with and without AsH3preflow are investigated using high-resolution scanning electron microscopy and transmission electron microscopy. This confirms that AsH3preflow suppresses island growth, allowing GaP epilayers to grow two-dimensionally, and also reduces the GaP-Si interfacial energy. © 1990 IOP Publishing Ltd.