Ellipsometric and gas-volumetric investigation of adsorption reactions on clean silicon and germanium

Abstract

The chemical adsorption of a few organic gases on clean silicon and germanium is discussed. The adsorption appears to depend strongly on the presence and number of dangling bonds at the surface. Structures for the adsorption complexes have been proposed, based on ellipsometric and gas-volumetric data. There is evidence that the adsorption complexes for CH₃Cl and CH₃Br on the (111) face have a reversible transition at higher temperatures, which regenerates dangling bonds. Thermodynamic calculations for this transition give information on the free energy of mutual compensation of these dangling bonds.