Evaluation of desorption activation energy of SiBr2 molecules

The chemical etching of silicon in Br2 ambient is considered. The desorption activation energy for an SiBr2 molecule is evaluated using experimentally measured dependences of etching rates on concentration of Br2 molecules. It is found that the desorption activation energy of SiBr2 molecules is equal to Ed = (1.52 ± 0.18) eV. Desorption of SiBr2 molecules is an etching-rate limiting process at high concentration of Br2 in the gas phase.