AVS 46th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoM

Paper TF-MoM6
High Rate a-Si:H Growth Studied by in situ Ellipsometry

Monday, October 25, 1999, 10:00 am, Room 615

Session: Fundamentals of PECVD
Presenter: A.H.M. Smets, Eindhoven University of Technology, The Netherlands
Authors: A.H.M. Smets, Eindhoven University of Technology, The Netherlands
B.A. Korevaar, Eindhoven University of Technology, The Netherlands
W.M.M. Kessels, Eindhoven University of Technology, The Netherlands
M.C.M. van de Sanden, Eindhoven University of Technology, The Netherlands
D.C. Schram, Eindhoven University of Technology, The Netherlands
Correspondent: Click to Email
In this contribution the results of in-situ HeNe rotating compensator ellipsometry measurements performed on hydrogenated amorphous silicon (a-Si:H) growth using an expanding thermal plasma are presented. This remote thermal plasma technique is developed as a promising tool for high deposition rate (10 nm/s) of a-Si:H on a roll to roll production line of low cost thin film solar cells on a flexible foil. The measurements can be simulated using an optical growth model consisting of a substrate layer, SiO@sub 2@ layer, intermediate layer, a-Si:H bulk layer and a top layer, corresponding to the surface roughness. Using this model the roughness evolution during deposition can be monitored. At deposition conditions at which "device quality" a-Si:H is grown the surface roughness is the smallest, indicating that roughness and material quality are related. The correlation between incorporation of SiH@sub 2@ complexes and the surface structure will be discussed. From the roughness evolution in time at various substrate temperatures the length scales which dominate the high rate a-Si:H growth can be deduced. The activation energy of the diffusion processes is also determined and its significance for the Matsuda-Perrin-Gallagher growth model will be discussed.