HYDROGEN EFFUSION FROM AMORPHOUS AND MICROCRYSTALLINE SILICON THIN-FILMS - HYDROGEN STABILITY AND BONDING CONFIGURATIONS

Effusion experiments were performed on hydrogenated (deuterated) amorp hous and thermally microcrystallized sputtered silicon films. In sputt ered amorphous silicon, the analysis of tile effusion spectra allows t o evidence clustered Si-H weak bonds in microvoids and isolated Si-H e mbedded in the compact tissue. When a magnetron cathode is used during the deposition process, the amorphous material is more homogeneous, t he local disorder more important, and a continuum of hydrogen configur ations is observed. The analysis of effusion spectra performed on post -hydrogenated (deuterated) microcrystalline silicon suggests the exist ence of cavities containing molecular hydrogen, weakly bonded hydrogen in small clusters and hydrogen trapped at grain boundaries.