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.