AVS 47th International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS1-MoA

Invited Paper PS1-MoA1
A Surface-Micromachined Miniature Inductively Coupled Plasma Generator

Monday, October 2, 2000, 2:00 pm, Room 310

Session: Emerging Plasma Applications
Presenter: J.A. Hopwood, Northeastern University
Authors: J.A. Hopwood, Northeastern University
O. Minayeva, Northeastern University
Y. Yin, Northeastern University
Correspondent: Click to Email
The design, fabrication, and characterization of a surface micromachined plasma generator are described. Although there are many applications for miniature plasma sources, this device is intended for electronic excitation of gas samples such that the presence of impurities and toxins may be detected using a micromachined optical emission spectrometer. The plasma is sustained without electrodes by inductively coupling a 450 MHz current into a region of low-pressure gas. The inductively coupled plasma source is surface micromachined on a glass substrate by electroplating a planar spiral inductor (5 mm in diameter) and two interdigitated capacitors. A plasma can be sustained in argon and air between 0.1 and 10 torr (13.3 Pa - 1333 Pa) and rf powers between 0.3 and 3 W. The argon ion density increases from 10@super 10@ to 10@super 11@ cm@super -3@ over this range of powers. The electron temperature decreases from 4 eV to 2 eV as the pressure increases from 0.1 to 1 torr. Network analysis of the plasma generator circuit shows that over 99% of the applied RF power can be absorbed by the device. Of this, @<=@50% is absorbed by the plasma and the remainder of the power is dissipated as ohmic heating. Scaling laws associated with the miniaturization of inductively coupled plasma sources will be discussed including the dependence of electron temperature on scaled chamber dimensions, the preferred frequency of operation, and rf power coupling efficiency.