An experimental study and modeling of Transformer-Coupled Toroidal Plasma processing of materials

The Transformer Coupled Toroidal Plasma (TCTP) source uses a high power density plasma formed in a toroidal-shaped chamber by transformer coupling using a magnetic core. The objectives of the thesis are (1) to characterize the TCTP source, (2) to understand the kinetics and limitations of species production by the remote TCTP source, and (3) to construct a generic model of plasma-surface interactions. By fitting the rovibrational bands of diatomic molecules such as N2, the temperatures of neutral gases were determined in the TCTP source. This was the first measurement of the neutral gas temperature of a high power density plasma in a toroidal geometry. An argon plasma was found to be around 2000K for a power density of 5 W/cm3. To avoid the necessity of N2 addition, the use of the C2 Swan bands of ( 3 3 d?g?a?u) were used to determine the neutral gas temperature of fluorocarbon plasmas. In a C2F6 discharge at a power density of 15 W/cm3, rotational and translational temperatures above 5000K were observed while vibrational temperatures above 8000K were found. The temperature measurements using C2 molecules were validated by the addition of N2 to the discharge and the caparison between the rotational temperatures of C2 and N2. These high neutral gas temperatures were justified by a power balance calculation that considered the thermal conduction, convection, ion bombardment, and dissociation energy losses. A linear dependence of the neutral gas temperature with the plasma power was found and is consistent with thermal and convention energy losses, where in both, the power loss linearly scales with the gas temperature.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Bai, Bo, Ph. D. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Herbert H. Swain.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/34975
• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Identifier URI

http://dspace.mit.edu/handle/1721.1/34975

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/34975