Hydrogen content of amorphous silicon films deposited in a multipole plasma

Hydrogenated amorphous silicon (a-Si:H) samples are prepared in highly controlled conditions in a multipole dc discharge. Hydrogen content of the film is systematically analyzed as a function of deposition parameters such as ion flow, ion bombardment energy E(ion), and substrate temperature. Hydrogen atomic concentration and profile are measured by nuclear reaction analysis. The essential role of ion bombardment is emphasized. Increasing deposition temperature and/or decreasing E(ion) results in a large decrease of the hydrogen content. Hydrogen-enriched surfaces are observed when E(ion) is less than about 10 eV. It is shown that Si(n)H(m)(+) bombardment during film growth produces a dense, hydrogen-rich material.