Pulsed corona plasma source characterization for film deposition on the inner surface of tubes
Ramasamy Pothiraja, Nikita Bibinov, Peter Awakowicz
JOURNAL OF PHYSICS D-APPLIED PHYSICS, Volume: 43, Issue: 49, Article Number: 495201, DOI: 10.1088/0022-3727/43/49/495201, Published: DEC 15 2010
A microplasma jet has been constructed for chemical vapour deposition on the inner surface of narrow long tubes and is tested on a quartz tube with the inner diameter of 6 mm and the outer diameter of 8 mm. A long plasma filament (> 100 mm) is generated inside the tube in argon with methane admixture. Depending on the quantity of admixture in argon, the negative as well as the positive corona discharges are ignited. Both modes of plasma are characterized using optical emission spectroscopy. For this purpose, nitrogen is admixed with argon and its emission is used for the determination of gas temperature, electron velocity distribution function and electron density at various places along the axis of the tube. The formation of active species, such as C, C(2) and CH during the dissociation of methane, is observed through their characteristic emission. The rate of methane dissociation is determined at various places along the axis of the tube during both modes of discharge. Since the chemical kinetics of the film growth process is different, different kinds of films are obtained during different modes of discharge.