AVS 46th International Symposium
    Plasma Science and Technology Division Thursday Sessions
       Session PS-ThM

Paper PS-ThM4
Plasma and Surface Chemistry in a Remote Silane Plasma Studied By Various Diagnostics and Related to a-Si:H Film Quality

Thursday, October 28, 1999, 9:20 am, Room 609

Session: Plasma-Surface Interactions II
Presenter: W.M.M. Kessels, Eindhoven University of Technology, The Netherlands
Authors: W.M.M. Kessels, Eindhoven University of Technology, The Netherlands
M.C.M. van de Sanden, Eindhoven University of Technology, The Netherlands
A.H.M. Smets, Eindhoven University of Technology, The Netherlands
B.A. Korevaar, Eindhoven University of Technology, The Netherlands
D.C. Schram, Eindhoven University of Technology, The Netherlands
Correspondent: Click to Email
A remote silane plasma used for fast deposition of device quality a-Si:H has been studied in detail and information about the contribution of particular species to film growth has been obtained. The creation and fluxes of silane radicals have been studied by means of various diagnostics like appearance potential mass spectrometry (SiH@sub 3@, SiH@sub 2@,H), UV absorption spectroscopy (SiH@sub 3@) and optical emission spectroscopy (SiH, Si). From ion mass spectrometry, revealing hydrogen poor cationic clusters up to Si@sub 10@H@sub n@@super +@, in combination with Langmuir probe measurements, the downstream ion chemistry is studied. It is shown that the deposition is dominated by radicals, while the ions have a contribution of approximately 7% to film growth. The silane radicals created can be influenced by changing the plasma source operation. It is shown that the deposition of a-Si:H can be altered from a SiH@sub 3@ dominated growth to a situation in which reactive silane radicals contribute significantly. This is accomponied by a decrease of the compound value for the surface reaction probability, as determined by an aperture-well assembly, a decrease of the film surface roughness and an improvement of the film quality in terms of structural and opto-electronic film properties. The compound value of the surface reaction probability is 0.33±0.05 for the conditions in which device quality a-Si:H is obtained. The role of the specific species in film growth and their influence on film properties is discussed.