OXIDE DESORPTION FROM INP UNDER STABILIZING PRESSURES OF P2 OR AS4

The oxide desorption processes of InP have been investigated under molecular-beam epitaxy conditions, determining thickness and composition of the surface layer by x-ray photoelectron spectroscopy and surface reconstructions by reflection high-energy electron diffraction (RHEED). Under P2 stabilization the oxide desorbs within 5 min at 490-degrees-C and a (2 x 4) reconstruction is observed. On the other hand, heating in a flux of As4 molecules results in the formation of an InAs layer at the top of the oxide, which strongly reduces the oxide desorption rate. The complete removal of the oxygen requires at least 520-degrees-C and typically leaves a 1-nm-thick overlayer of InAs. In this case RHEED gives no indication whether the surface is oxide free.