XPS STUDY OF XECL EXCIMER-LASER-ETCHED INP

X-ray photoelectron spectroscopy (XPS) and scanning electron microscop y (SEM) have been applied to investigate the surface chemistry and mor phology of InP wafers photochemically etched under 308 nm illumination from a XeCl excimer laser. The etching experiments were carried out a t ambient temperature and in a low-pressure (1 mu bar) atmosphere of C l-2 (10%) diluted in He. During the process, the samples were exposed to laser radiation with fluences of 73 mJ/cm(2) or 114 mJ/cm(2). Both fluence values are below the ablation threshold of 140 mJ/cm(2) for In P, The mapping of the photoelectron spectral line intensities of In (3 d(5/2)), Cl (2p(3/2)), and P (2p(3/2)) displayed the distribution of I n-Cl and In-P compounds on the surface of the wafer. The chemical comp osition and morphology of the etched surface were found to be dependen t on laser fluence. Surfaces with a fine granular structure were obser ved at a lower fluence, while at higher fluences, surfaces with a line ar grating-like structure were formed. More chlorine is bound to the s urface prepared at a higher fluence. (C) 1998 Elsevier Science B.V.