Chemical and physical effects in oxygen incorporation during the metalorganic vapor phase epitaxial growth of GaAs

Abstract

Combined growth, electrical and morphological studies of the influence of oxygen incorporation were carried out on metalorganic vapor phase epitaxy (MOVPE) grown GaAs. The impact of oxygen incorporation on the growth front morphology has been systematically investigated. Oxygen is incorporated into the growing film through the use of an Al-based precursor, (C 2H 5) 2AlOC 2H 5, which contains Al directly bonded to an oxygen atom. The oxygen appears to be preferentially incorporated at the metal-terminated steps. The presence of one or more Al atoms at the step edge is believed to be responsible for the incorporation of electrically active oxygen into the lattice. Oxygen at the growth front, particularly at the step edges, leads to the gradual roughening of the surface structure. High levels of oxygen, [O] ≥ 10 18cm −13, lead to the breakdown of the periodic surface structure found in nominally undoped MOVPE GaAs with a very rough hillock structure resulting. Models for the impact of oxygen on the growth front evolution are presented. The study of the simpler GaAs:O system can provide a basis for understanding the role of oxygen in more complex semiconductor systems.