AVS 49th International Symposium
    Plasma Science Tuesday Sessions
       Session PS1-TuA

Paper PS1-TuA6
Characteristics of Miniature Microwave Excited Plasma Discharges

Tuesday, November 5, 2002, 3:40 pm, Room C-103

Session: Microdischarges
Presenter: T.A. Grotjohn, Michigan State University
Authors: T.A. Grotjohn, Michigan State University
D. Story, Michigan State University
S. Zuo, Michigan State University
J.J. Narendra, Michigan State University
A. Wijaya, Michigan State University
J. Asmussen, Michigan State University
Correspondent: Click to Email
Small microwave generated plasma discharges are characterized to determine their properties for discharges with sizes ranging from 0.3 mm to 10 mm and for a wide range of discharge aspect ratios. The discharge characteristics investigated included microwave power density, plasma density, electron temperature and gas temperature. The outcome of this investigation to be presented is an understanding and quantification of the microwave power density needed to operate small discharges of specific sizes, shapes, densities and gas compositions. Three microwave plasma sources are used to accomplish this investigation including (1) a highly flexible and adjustable coaxial waveguide source with the plasma generated in an adjustable gap located in the center conductor, (2) a microstrip-line based plasma source with the discharge created in a long quartz tube of 0.3 mm to a few mm in inside diameter, and (3) a microwave powered electrode system where the plasma is formed at the end of the electrode and the plasma is either unbounded or confined in a small spherical, long cylindrical or flat disk shaped chamber. The plasma compositions investigated include argon, nitrogen and hydrogen discharges. The diagnostic measurements are performed using Langmuir probes and optical emission spectroscopy. The plasma characteristics measured and modeled indicate that as the characteristic dimension of the discharge decreases to less than 1 mm, the power densities approach and exceed 1000 W/cm@super 3@ and the plasma densities are above 10@super 13@ cm@super -3@.