Mode identification of surface waves excited in a planar microwave discharge

Abstract

A planar high-density (∼10 12 cm −3 ) plasma, 22 cm in diameter and 9 cm in length, is produced by a 2.45 GHz microwave radiation of 500 W through small slot antennas in argon at 20-350 Pa without a magnetic field. Several types of azimuthal and radial standing wave mode pattern are observed in the optical emission from the plasma depending on the discharge conditions. The microwave field in the plasma measured by a movable antenna decreases exponentially in the axial direction from the quartz wall adjacent to the slot antennas, thus suggesting the propagation of surface waves in the r, θ directions. The measured azimuthal microwave field distributions and the optical emission pattern clearly show a mode transition of the standing surface wave from a TM 33 mode to a TM 62 mode when the pressure is decreased from 140 to 44 Pa at the constant power of 400 W. Here TM mn denotes the transverse magnetic mode of azimuthal mode number m and radial mode number n. A wave dispersion analysis based on a one-interface uniform-density model predicts these modes in a range of electron densities corresponding to those measured by a Langmuir probe in the experiment.

Effects of methane gas flow rate on the optoelectrical properties of nitrogenated carbon thin films grown by surface wave microwave plasma chemical vapor deposition

“…The SWMP-CVD was produced in a 300 mm, cylindrical vacuum chamber by introducing a 2.45 GHz microwave through a quartz window via slot antenna. The microwave is introduced through the slot antennae drops exponentially below the quartz window where the electron density exceeds the cutoff density [12,13]. A high density plasma with a uniform electron density more than 10 11 cm À 3 was formed in the vacuum chamber and broadened in the downed stream region due to the particle diffusion.…”

Effects of low-temperature surface-wave plasma treatment with various gases on surface modification of chitosan

“…The plasma reactor consisted of a cylindrical vacuum chamber with a microwave launcher and 2.45 GHz microwave generator [25,26]. The vacuum chamber was 400 mm in diameter and 400 mm in height.…”

Microstructure and chemical bond evolution of diamond-like carbon films machined by femtosecond laser

“…The details of the system were described elsewhere [23][24][25][26][27][28]. Thick DLC coating with about 28 µm was grown on carbon/carbon substrate (C/C substrate) which was made from tow-dimensional PAN-based needle carbon fiber perform densified during chemical vapor infiltration (CVI) process.…”