The mechanism of gallium arsenide etching in a chlorine-argon plasma was st
udied. The absorption-desorption model was proposed which explains an incre
ase in etching rate upon chlorine dilution with argon by enhancement of the
efficiency of active site cleaning with plasma UV radiation and ion fluxes
. The processes of desorption of etching products from the surface by ions
and UV photons were shown to be energetically favored. The amount of active
sites cleaned per ion or photon was calculated. The addition of argon was
assumed to change the proportion of active sites. Procedures for calculatin
g fluxes of reactive species onto the surface and the probability of ultrav
iolet light- and ion-induced desorption were detailed.