X-ray photoelectron spectroscopy has been used to investigate the interacti
on of xenon difluoride at chemical vapour deposited, polycrystalline diamon
d surfaces. Dissociative chemisorption, resulting in the formation of adsor
bed fluorine up to monolayer coverages, occurs on the clean surface with a
sticking probability of approximately 10(-4). Prehydrogenation of the diamo
nd, increases the initial reactive sticking probability, but reduces the sa
turation fluorine coverage observed. Two forms of adsorbed fluorine are cle
arly detected. The most thermally stable species, which is produced during
initial xenon difluoride exposures, is attributed to covalently bonded carb
on monofluoride functionalities. A second species, which is more weakly bou
nd, has the characteristics of semi-ionic fluorine, which has been observed
previously in the interaction of fluorine with other carbon forms. Thermal
desorption studies show that the adsorbed fluorine desorbs over a large te
mperature range (40-800 degreesC), reflecting the varying thermal stabiliti
es of the differing populated states. Etching of a fluorine-saturated surfa
ce with hydrogen atom fluxes shows two main regimes; initial rapid removal
of the semi-ionic fluorine species, followed by the very slow abstraction o
f covalent CF species. The comparative behaviour of the chemically vapour d
eposited diamond films with diamond single crystal surfaces, with regard to
the chemistry observed, is discussed. (C) 2001 Elsevier Science B.V. All r
ights reserved.