Dresden 2011 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 12: Layer Deposition Processes

DS 12.5: Vortrag

Montag, 14. März 2011, 18:15–18:30, GER 38

Electrical and structural properties of magnetron sputtered hydrogenated amorphous Silicon films — •Frank Nobis, Hartmut Kupfer, Evelyn Breyer, Philipp Schäfer, Dietrich R. T. Zahn, and Frank Richter — Chemnitz University of Technology, Institute of Physics, 09107 Chemnitz, Germany

Magnetron sputtering could represent a valuable part of a low cost solar cell in line technology using amorphous silicon (a-Si) if a crucial problem could be overcome: In magnetron discharges, high energy particles are hitting the growing films. They cause a high defect density in the a-Si films, drastically reducing the efficiency of doping atoms.

We have investigated doped a-Si:H films sputtered by a pulsed DC magnetron discharge. The hydrogen content in the films was varied by changing the hydrogen partial pressure in the process gas. We found a saturation of the hydrogen content in the films at about 20 at.%. The electrical resistivity of the films was investigated at varied temperature to get information about the charge carrier transport. The results will be discussed in terms of different hopping conductivity mechanisms. The investigations have shown that only a negligible fraction of the incorporated doping atoms are electrically active. Therefore, the goal of continued investigations is to increase dopant activation by changing the process parameters and by deposition at elevated substrate temperatures. Furthermore, the influence of substrate bias voltage and hydrogen partial pressure during deposition on the surface and structure of the film is reviewed.