Laser CVD of Filaments
Lasers have been used to chemically vapor deposit materials since the 1970’s. The fine focus achievable with the laser beam allows deposition to be carried out on a substrate much like hand-writing. The formation of a filament simply requires moving the filament to keep the laser beam focused on or near the depositing tip of the filament. Deposition rates can be very rapid because of the high mass transport rate that can be achieved, although the total mass deposited is low. Multiple beams can be used to increase the number of filaments being formed, but the high deposition rate would be sacrificed somewhat. However, the process is attractive for producing small amounts of new high temperature materials in the easily tested filament form. The process is also amenable to easily making more complicated shapes such as coils that could be used for heating or other applications. Deposition kinetics are different for cases where deposition is from the original deposition molecule or early formed fragment, compared to intermediates formed by subsequent gas phase reactions.
P. VINCENZINI and M. SINGH
K.D. Frischknecht and R.J. Diefendorf, "Laser CVD of Filaments", Advances in Science and Technology, Vol. 50, pp. 115-123, 2006