STRUCTURE OF CHEMICALLY PREPARED PASSIVATION LAYERS ON SINGLE CRYSTAL SEMICONDUCTOR SURFACES

Monolayers of S and Cl have useful passivation properties for group IV and III–V semiconductor surfaces. The structures of Ge(111)–Cl; GaAs(111)–Cl; GaAs(111)A–S, GaAs(111)B–S and GaAs(001)–S monolayer-passivated single crystal semiconductor surfaces have been studied using synchrotron radiation X-ray absorption fine structure spectroscopy (XAFS). The near edge and extended fine structure signals are interpreted using comparisons to multiple scattering XAFS calculations and, in the cases of Ge(111)–Cl and GaAs(111)–Cl, comparison to first-principles calculations. Relationships between the surface structure and the development of improved passivated surfaces are discussed.