Ion beam analysis of amorphous silicon films produced by magnetron sputtering

The properties of a-Si:H thin films prepared by the magnetron sputtering thechnique are studied by different analytical methods. The Rutherford backscattering provides data on the a-Si film thickness and Ar incorporation whereas the hydrogen concentration is measured by the elastic recoil detection technique. The Ar concentration remained constant (0.5 to 1 at%) independently of the rf-power, Ar-gas pressure, and cathode-target distance. The incorporated concentration of H-atoms increases linearly with the H-gas partial pressure. A strong correlation is observed between the H-content and the resistivity of the a-Si films. The electrical measurements show a decrease of the conductivity by about ten orders of the magnitude with increasing hydrogen content. The estimated activation energy of the transport in the extended states amounts to 0.76 eV. (author)