PECVD DEPOSITION OF DEVICE-QUALITY INTRINSIC AMORPHOUS-SILICON AT HIGH GROWTH-RATE

The combined influence of RF-power density (RFP) and silane flow-rate (phi) on the deposition rate of plasma-enhanced chemical vapour deposition (PECVD) intrinsic amorphous silicon has been investigated. The correlation of the results obtained from the characterisation of the material with the silane deposition efficiency, as deduced from mass spectrometry, has led to an interpretation allowing to deposit intrinsic amorphous-silicon films having an optical gap of 1.87 eV and a photoconductive ratio (ratio of ambient-temperature conductivities under 1 sun AM1 and in dark) of 6 orders of magnitude at growth rates up to 10 angstrom/s, without any structural modification of the PECVD system used. Such results are considered of high relevance regarding industrial competitiveness.