Optical Emission and Microwave Field Intensity Measurements in Surface Wave-Excited Planar Plasma

Abstract

A large-planar (22 cm diam.) high-density ( ∼2×1012 cm-3) plasma is produced in argon gas at 140 Pa by 2.45 GHz–1 kW discharges, using a microwave launcher of small slot antennas. The two-dimensional distributions of optical emission intensities as well as microwave field intensities are measured near the plasma surface irradiated with microwaves. Both the optical emission and the microwave field clearly show stationary patterns of azimuthal mode m=3 and radial mode n=3 at higher pressures (140 Pa), while a mode change to m=6 and n=2 is observed at lower pressures (44 Pa). These patterns are attributed to the excitation and absorption of standing surface waves near the cutoff layer.

Travelling-wave-sustained discharges

“…The application-orientated research on TWSDs led to introducing changes of the shape of the discharge vessels aiming at reaching large area discharge production [166,167] as well as to inventing new types of launchers for planar discharges [168][169][170][171][172][173][174][175][176][177][178][179][180][181][182][183] and short tubular discharges [184][185][186][187][188][189][190][191][192] and also new launchers for discharge production in the microwave range [193]. Many possibilities for the use of TWSDs for surface processing and film deposition [12,149,[194][195][196][197][198][199][200][201][202][203][204][205][206][207][208][209]…”

Detection of localized hot electrons in low-pressure large-area microwave discharges

“…Recently, especially in connection with the microelectronic industry, growing attention has been paid to largearea microwave plasma sources working without static magnetic fields. [1][2][3][4][5] In these sources, the overdense plasma is produced by guided electromagnetic waves propagating along the plasma-dielectric interface. Plasma inhomogeneity at the interface introduces a locally enhanced electric field ͑component perpendicular to boundary͒ near the region, where the local plasma frequency p equals the applied field frequency .…”

Spatio-temporal behavior of microwave sheath-voltage combination plasma source

“…In general, dielectric-bounded SWP sources employ dielectrics such as a quartz plate [3][4]6] or a quartz tube [7][8][9][10], along which high density plasmas are sustained by electromagnetic waves travelling along plasma-dielectric surface boundaries [10][11][12][13][14][15][16][17][18][19][20][21]. Dielectric-bounded SWP sources have never been used for sputtering, because they are not generated near and along a metal target as in conventional magnetron sputtering sources [1].…”