AVS 50th International Symposium
    Plasma Science and Technology Thursday Sessions
       Session PS1-ThM

Paper PS1-ThM10
Plasma Chemistry and the Growth Kinetics of Silicon Nitride Deposited by the SiH@sub 4@-N@sub 2@ Reactant Mixture

Thursday, November 6, 2003, 11:20 am, Room 314

Session: Plasma-Surface Interactions: Deposition
Presenter: F.J.H. Van Assche, Eindhoven University of Technology, The Netherlands
Authors: F.J.H. Van Assche, Eindhoven University of Technology, The Netherlands
J. Hong, Eindhoven University of Technology, The Netherlands
M.C.M. van de Sanden, Eindhoven University of Technology, The Netherlands
W.M.M. Kessels, Eindhoven University of Technology, The Netherlands
Correspondent: Click to Email
Plasma ions and radicals in a remote plasma operated on an Ar-H@sub 2@-N@sub 2@-SiH@sub 4@ mixture have been studied by several diagnostics such as Langmuir probe measurements, ion mass spectrometry, cavity ringdown spectroscopy, and threshold ionization mass spectrometry. It is shown that the H radicals that emanate from the plasma source react with the SiH@sub 4@ admixed downstream and create a high SiH@sub 3@ density. Si and SiH radicals have also been measured but they have a much lower density in the downstream plasma. Ground-state N radicals emanating from the plasma source do not react with the SiH@sub 4@ injected downstream leading to a high N density under the silicon nitride deposition conditions. This has lead to the conclusion that N and SiH@sub 3@ radicals dominate the silicon nitride growth process as has also been confirmed by the correlation between the SiH@sub 3@ and N density in the plasma and the incorporation flux of Si and N atoms into the silicon nitride films. Furthermore, from this correlation very reasonable sticking probabilities of the N and SiH@sub 3@ radicals have been obtained. >From these results, the following kinetics for silicon nitride growth from the N@sub 2@-SiH@sub 4@ reactant mixture are proposed: During deposition an amorphous silicon-like surface layer is created by the SiH@sub 3@ radicals and simultaneously this amorphous silicon-like surface layer is nitridated by the N radicals leading to silicon nitride formation. Further support for this mechanism is obtained by experiments in which silicon nitride films have been created by exposing amorphous silicon films to a high flux of N radicals.