Chemical and structural analysis by ellipsometry and x-ray reflectometry of thin sulfide layers grown on InP

Abstract Spectroscopic ellipsometry at high lateral resolution and grazing X-ray reflectometry are used as non-destructive techniques and as complement to X-ray photoelectron spectroscopy, to characterize the sulfide layers formed at the surface of InP by plasma or thermal way. Modeling permits the determination of the thicknesses of the layers and their homogeneity, of the existence or the absence of a superficial residual natural oxide, and of the surface and interface roughnesses. We show that the sulfide plasma layer can lead, with InP, to a sharper interface than the thermal sulfide layer, albeit with a lower composition in phosphorus and sulfur.