AVS 47th International Symposium
    Thin Films Wednesday Sessions
       Session TF+EL-WeA

Paper TF+EL-WeA10
Investigation of the Subsonic Beam behaviour of an Expanding Thermal Plasma used to Deposit Silicondioxide like Films

Wednesday, October 4, 2000, 5:00 pm, Room 203

Session: In-situ Characterization of Thin Film Growth
Presenter: M.F.A.M van Hest, Eindhoven University of Technology, The Netherlands
Authors: M.F.A.M van Hest, 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
Silicondioxide like films are deposited using a remote thermal argon plasma generated by means of a cascaded arc (p=0.1 - 0.2 bar). Into this remote argon plasma, which expands into a vacuum vessel (p=0.1 mbar), two precursors are injected. First Oxygen is injected at the arc nozzle, and downstream HMDSO (hexamethyldisiloxane) is injected by means of an injection ring. By studying the behaviour of the expanding beam for various plasma conditions a better insight is created in the plasma chemistry. The plasma is analysed by means or Langmuir probe and Pitot tube measurements. Furthermore the growth is studied in situ by means of HeNe ellipsometry and infrared reflection absorption spectroscopy. By means of the Pitot tube the expanding gas velocity can be measured at various positions in the plasma reactor, and with this the gas flow pattern in the reactor can be determined. First of all the flow pattern is studied for a pure argon plasma. This is done as function of the carrier gas flow (argon) and arc current, but also for different background pressures. Second the flow pattern is studied when the depositing precursors are added to the expanding argon plasma. The Pitot tube measurements show that in the plasma reactor there is a recirculation flow on the outside of the expansion. The Langmuir probe measurements show the ion density in the plasma beam. From the combination of the Langmuir probe measurements and the Pitot tube measurements a possible dissociation mechanism for the deposition precursors will be derived. These results will be combined with the in situ measurements of the film growth to obtain insight in the film growth mechanism.