X-ray and UV photoelectron spectroscopy of oxide desorption from InP under As4 and/or Sb4 overpressures: exchange reaction As ⇔ Sb on InP surfaces

We report here on the oxide desorption of InP substrates in a molecular beam epitaxy (MBE) chamber, under As4 and/or Sb4 overpressures. In situ characterizations including reflection high-energy electron diffraction (RHEED), X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) are used. We show that even if the deoxidation is feasible using one of the different beam pressures, the less critical temperature control leading to a good surface quality is obtained under (As4 + Sb4) combined pressures. The oxide desorption is complete at a substrate temperature of 530°C far below the In-stabilized surface. In this case, XPS measurements show the formation of about 2 ML thick InAsxSb1 − x layer on top of InP. An annealing of such a surface under As4(Sb4) up to 480°C led to the formation of ∼2 ML thick pure InAs (InSb) layer on top of InP.