AMORPHOUS GALLIUM PHOSPHATE THIN-FILMS - GA AND O K-EDGE ABSORPTION-SPECTROSCOPY

Amorphous dielectric gallium phosphate thin films of various compositi ons are obtained on silicon substrate by the ''pyrosol'' process. We r eport, in this paper, the results of a structural characterization of these deposits. The atomic surroundings of gallium atoms have been det ermined by a Ga K-edge X-ray absorption study. Oxygen K-edge XANES mea surements, completed by O 1s core-level XPS data collection, were carr ied out in order to probe the oxygen environment. In phosphorous-rich thin films, gallium atoms are in mixed surroundings constituted by bot h tetrahedral GaO4 and octahedral GaO6 sites. The oxygen atoms are div alent, and we pointed out the coexistence of Ga-O-P and P-O-P linkages . In gallium-enriched deposits, GaO6 sites are predominant. The oxygen atoms are mainly dicoordinated to gallium ones, while some are non-br idging.