E‐H Transition in Argon/Oxygen Inductively Coupled RF Plasmas

Abstract

This contribution presents results of comprehensive investigation of the E-H transition in an inductively coupled radio frequency argon/oxygen discharge at 13.56 MHz. For the characterization of the discharge arrangement, the spatial magnetic and electric field components of the planar coil in vacuum are calculated and provide information about the electron heating region. The used double coil leads to a radial symmetric field distribution. Further, voltage and current probe measurements reveal the inductivity of the coil and the phase shift between the coil voltage and the current. As a result, the coil current and the RF voltage are directly proportional. The phase shift is nearly constant in the E-mode and decreases slightly in the H-mode. The positive ion saturation current as well as the line integrated electron density are measured by means of Langmuir probe and 160 GHz microwave interferometer, respectively, to study the mode transition in argon with different oxygen contents. The positive ion saturation current and the electron density decrease with increasing oxygen admixture at fixed pressure and RF power. The onset and the way of the E-H transition strongly depend on the oxygen content. The mode transition of a pure argon discharge is step like and changes to a continuous mode transition with the admixture of oxygen.

Gas temperature measurements in a pulsed, low-pressure inductively coupled plasma in oxygen

“…rotational temperatures determined by O 2 OES gave the same value for pure O 2 and O 2 with 15% Ar plasmas. This is in line with measurements by Wegner et al 29) of ion saturation current, line-integrated electron density and E-H mode transition voltages for a range of Ar/O 2 mixtures in a 10 Pa ICP. For pure O 2 and 25% Ar, the values are within roughly 10% of each other, giving some confidence that also the gas temperature is minimally affected by the admixture.…”

E‐ and H‐mode transition in a low pressure inductively coupled ammonia plasma

“…The transition between capacitive and inductive mode is usually abrupt and occurs when the discharge power reaches a certain value, which depends on peculiarities of a particular discharge configuration. Such transitions have been studied for many gases by different authors …”

“…Such transitions have been studied for many gases by different authors. [1][2][3][4][5][6] Plasma created by electrodeless discharges represents a rich source of reactive gaseous species. As in many other types of discharges, the gaseous molecules are excited, dissociated or/and ionized upon interacting with electrons from the high-energy part of their distribution function.…”