IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Thin Films Tuesday Sessions
       Session TF-TuM

Paper TF-TuM7
High Growth Rate Deposition of a-SiN@sub x@:H Films for Photovoltaic Applications

Tuesday, October 30, 2001, 10:20 am, Room 123

Session: Optical Thin Films
Presenter: J. Hong, Eindhoven University of Technology, The Netherlands
Authors: J. Hong, Eindhoven University of Technology, The Netherlands
W.M.M. Kessels, Eindhoven University of Technology, The Netherlands
F.J.H. Van Assche, Eindhoven University of Technology, The Netherlands
D.C. Schram, Eindhoven University of Technology, The Netherlands
M.C.M. van de Sanden, Eindhoven University of Technology, The Netherlands
Correspondent: Click to Email
A new technique has been developed for the deposition of amorphous silicon nitride (a-SiN@sub x@:H) films at deposition rates up to ~200 Å/s by injection of SiH@sub 4@ into an expanding Ar/H@sub 2@/N@sub 2@ plasma. This so-called expanding thermal plasma (ETP) technique is relevant for high-throughput deposition of a-SiN@sub x@:H anti-reflection (AR) coatings on industrial Si solar cells, where the a-SiN@sub x@:H can simultaneously lead to both bulk and surface passivation. Silicon nitride films with different Si/N ratios and hydrogen concentrations have been deposited on different types of Si solar cells. It has been revealed that the optical properties can be fully tuned to obtain an optimized AR matching with the Si substrate while real-time ellipsometry is used as feedback during processing. Film homogeneity measurements revealed less than 5% variation over 10x10 cm@super 2@ cells. Bulk passivation of multi-crystalline Si cells has been suggested by an enhanced red response of the coated cells, although preliminary results on surface passivation have not yet revealed sufficient reduction of the surface recombination on mono-crystalline Si cells. More data on real solar cells will be presented. The plasma chemistry has been studied by threshold ionization mass spectrometry and cavity ring down spectroscopy. These measurements suggest the creation of SiH@sub 3@ radicals by atomic H from the plasma source leading to a neutral-dominated deposition of a Si top layer, followed by subsequent nitriding by atomic N. Real-time attenuated total reflection infrared spectroscopy is applied to extend the insight into this deposition mechanism.