AVS 52nd International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS-WeA

Paper PS-WeA9
Atmospheric Microplasma-on-a-Chip Operating in Air

Wednesday, November 2, 2005, 4:40 pm, Room 302

Session: Atmospheric Plasmas and Microdischarges
Presenter: J. Hopwood, Northeastern University
Authors: J. Hopwood, Northeastern University
F. Iza, Pohang University of Science & Technology, Korea
Correspondent: Click to Email
In this paper, an atmospheric pressure plasma-on-a-chip operating in air is described. The microplasma is ignited and sustained by microwave power (900 MHz, 3 watts) from a common cell phone power amplifier. The discharge is sustained within a 25µm gap formed in a microstripline split-ring resonator. The microstrip transmission lines are surface micromachined on a 22 mm diameter aluminum oxide wafer using electroplated copper and gold. The high quality factor (Q) and narrow discharge gap of the split-ring resonator result in electric field strengths in excess of 10 MV/m prior to plasma ignition. The discharge appears as an intense filament, but is not in thermal equilibrium as the measured rotational temperatures for the second positive system of nitrogen are 500-700 K in atmospheric pressure air. The impedance of the microplasma is found by measuring the microwave reflection coefficient of the resonator as a function of frequency. From the plasma impedance, the electron density is found to be on the order of 10@super 14@ cm@super -3@ in atmospheric pressure argon. Lifetime testing shows that the micro-electrodes are not eroded by ion bombardment after 100 hours operating in air at 3 watts. Applications for this microplasma include portable chemical analysis by optical emission spectrometry and ion mobility spectrometry. This work is supported by the NSF under Grant No. DMI-0078406.