大気圧プラズマCVDにより高速形成した多結晶Si薄膜の構造に対するSiH_4濃度の影響

概要

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Polycrystalline silicon films were prepared by APPCVD (atmospheric pressure plasma CVD) with high deposition rate. The dependence of the Si film structures and deposition rate on silane concentration was investigated. The film growth has two stages depending on silane concentration. It was found that the silane concentration 0.02% was turning point of growth mode when plasma power was 2500W, hydrogen concentration was 10%. The achieved maximum deposition rate was 9nm/sec when silane concentration was 0.1%. The grain size was a few μm and the Si films were found to be composed wedge-shape grains perpendicular to substrate surface. Each crystallinity of the prepared Si films under all experimental conditions was above 80% from Raman scattering spectra. In region of low silane concentration, the crystallinity decreased with increase in silane concentration. The grain orientation of Si film was also strongly depended on silane concentration. The almost grains indicated <110> orientation under low silane concentration condition by XRD. But, higher silane concentration, the other crystal orientations, <111>, <311> became stronger. This orientation dependence on silane concentration was considered to be caused by the competition process between grain growth rate depending on crystal orientation and etching rate of films by atomic hydrogen generated by atmospheric plasma.
社団法人精密工学会の論文
2005-11-05