Surface preparation for molecular beam epitaxy-regrowth on metalorganic vapour phase epitaxy grown InP and InGaAsP layers

MBE regrowth on MOVPE grown InP and InGaAsP (1.06 mu m) layers was found to demand appropriate surface treatment for not sacrificing epitaxial growth performance. Wet chemical etching using a sulphuric acid based solution as well as surface oxidation using UV light/ozone exposure were found to give very satisfactory and basically equivalent results. Particularly with the quaternary material, both methods prove to be destructive in that a non-neglible amount of material is removed from the surface. The removed thickness tends, however, to be smaller with the UV/ozone based process, an advantage, which becomes especially apparent in the presence of lower band gap InGaAs(P) layers which are strongly attacked by the sulphuric acid etchant.