AVS 52nd International Symposium
    Thin Films Monday Sessions
       Session TF-MoP

Paper TF-MoP50
Inhomogeneous Rarefaction of the Process Gas in a Direct Current Magnetron Sputtering System

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Aspects of Thin Films Poster Session
Presenter: F.J. Jimenez, University of Alberta, Canada
Authors: F.J. Jimenez, University of Alberta, Canada
S.D. Ekpe, University of Alberta, Canada
S.K. Dew, University of Alberta, Canada
Correspondent: Click to Email
The interactions between energetic particles and the sputter gas in a magnetron sputtering system have strong effects on the growth, structures and properties of the film. These interactions result in inhomogeneous rarefaction of the gas in the space between the target and substrate, and affect the transport of particles towards the substrate. A hybrid Monte Carlo and fluid model is developed to simulate 3-dimensional gas rarefaction due to the sputtering of metals in Argon, Neon and Krypton. The governing equations are solved iteratively in a 3D space with a non-uniform grid (octree). Collision events between the sputtered particles and the process gas are assumed as the dominant source of gas heating, however, the effect of the reflected neutrals is also included in the model. Gas rarefaction profiles have been predicted for different process conditions. Results compare well with experimental results. The location of the highest rarefaction depends strongly on pressure, power, target material and location of the substrate plane relative to that of the target. The extent of rarefaction depends further on the thermal conductivity of the gas. Materials with high sputtering yield, like Silver, show more rarefaction than those with low sputtering yield, like Tungsten and Aluminum. Tungsten, as a result of a higher target to gas mass ratio, shows more of the effect than Aluminum. For a 75 mm target at 300 W and 10 mTorr a rarefaction of about 65% is obtained for the sputtering of Aluminum in Argon gas, with the substrate plane located at 10 cm in front of the target.