J. Phys. IV France 7 (1997) C2-975-C2-977
Amorphous Gallium Phosphate Thin Films : Ga and O K-Edge Absorption SpectroscopyF. Tourtin1, P. Armand1, A. Ibanez2, G. Tourillon3 and E. Philippot1
1 LPMC, UMR 5617, Case 003, Place E. Bataillon, 34095 Montpellier cedex 05, France
2 Laboratoire de Cristallographie, CNRS, 25 avenue des Martyrs, BP. 166, 38042 Grenoble cedex 09, France
3 LURE, Bât. 209D, Centre Universitaire Paris-Sud, 91405 Orsay cedex, France
Amorphous dielectric gallium phosphate thin films of various compositions are obtained on silicon substrate by the "pyrosol" process. We report, in this paper, the results of a structural characterization of these deposits. The atomic surroundings of gallium atoms have been determined by a Ga K-edge X-ray absorption study. Oxygen K-edge XANES measurements, completed by O 1s core-level XPS data collection, were carried out in order to probe the oxygen environment. In phosphorous-rich thin films, gallium atoms are in mixed surroundings constituted by both tetrahedral GaO4 and octahedral GaO6 sites. The oxygen atoms are divalent, 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-bridging.
© EDP Sciences 1997