J. Phys. IV France 02 (1991) C2-185-C2-191
ANALYSIS OF CVD BY SURFACE ANALYSIS TECHNIQUES AND IN-SITU MASS SPECTROMETRYP.A.C. GROENEN, J.G.A. HÖLSCHER and H.H. BRONGERSMA
Department of Physics, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands
The reaction between WF6 and Si has been studied with a specially designed mass spectrometer set-up, and by AES depth profiling. The time development of the reaction is monitored via the reaction product SiF4. Two stages can be distinguished. The first stage is a quick rise to a maximum SiF4 signal. During this stage most of the F is absorbed in the Si, forming a reaction layer of SiFn moieties. The tungsten covers the surface in an open structure. In the second stage, these SiFn moieties desorb after the addition of the necessary F atoms, supplied by adsorbing WF6. The total amount of SiFn moieties decays exponentially with time. The rate limiting step is the formation of SiF4 with an activation energy of 1.6 ± 0.2 eV, probably the addition of F to SiF3.
© EDP Sciences 1991