SULFURIZATION OF INP(001) SURFACES STUDIED BY X-RAY PHOTOELECTRON ANDX-RAY-INDUCED AUGER-ELECTRON SPECTROSCOPIES (XPS XAES)/

Surface chemistry of n- and p-doped InP(001) after treatment with sulf ur from different sources has been investigated by XPS/XAES measuremen ts. Core level lines, valence band spectra and Auger transitions were related to changes in surface chemistry and band bending. Both high re solution chemical shifts and the Auger parameter concept were used for the identification of chemical species. Sulfurization was performed b y dipping the chemically cleaned sample into a (NH4)(2)S solution or b y exposing it to S-2 or H2S molecules in UHV. Depending on the source and on the annealing temperature several sulfur compounds were observe d on the surface and identified as sulfides with sulfur substituting p hosphorus or with sulfur as surface atom, and as polysulfide probably with one sulfur atom in a terminal position. Changes of surface Fermi energy position and thus band bending were investigated.