Deposition of Polycrystalline Silicon by Pyrolysis of Silane in Argon

Abstract

Deposition of silicon on thermally grown silicon dioxide substrates by pyrolysis of silane in argon is postulated as a three‐step process involving adsorption and decomposition of silane on, and desorption of hydrogen from the substrate surface. This postulate was verified by experimental data. The morphology of the polysilicon films was strongly affected by the cleaning process employed before the silicon dioxide was grown. To obtain an optically smooth surface, it was mandatory that the silicon subtrate be cleaned by a strong oxidizing agent. The grains of the polysilicon film were randomly oriented and the grain size increased as the deposition temperature was increased.