Fundamental study on filter effect of confronting divergent magnetic fields applied to low-pressure inductively coupled plasmas

Abstract

The electron motion under confronting divergent magnetic fields (CDMFs) applied to inductively coupled plasmas was simulated using a Monte Carlo method. The CDMFs induced by two coaxial dc coils confined electrons in one side of the separatrix of the CDMFs. However, electrons diffused across the separatrix mainly in two ways. One was the displacement of their gyrocenters due to scattering near the outer part of the separatrix. This process tended to occur for high-energy electrons with correspondingly large gyroradii. The other was passage through the weak magnetic field around the center. This process was allowed for low-energy electrons. The position-dependent selectivity about the electron energy was pointed out as a seed property for applications of the separatrix as a magnetic filter or shutter. The mechanism by which the functions of the separatrix emerge was explained from a viewpoint of electron motion under the CDMFs.

Stochastic electron energy gain in inductively coupled magnetized plasmas accompanying electron reflection at chamber wall

“…This is comprehensible because the ratio of the velocity components assigned for v x tends to be high in the diffuse reflection model defined as Eqs. (4)- (6). The factor that directly It is a natural result that the L(x) andε(x) values are high in the vicinity of the wall corresponding to the high G(x) values there.…”

Analysis of electron heating due to partial resonance in an inductively coupled plasma under confronting divergent magnetic fields

“…For example, the magnetic neutral loop discharge (NLD) plasma [1][2][3][4][5][6][7][8] for etching are high-density inductively coupled plasma (ICP) generated under a quadrupole magnetic field (QMF). As well, the X-point plasma, 9,10) which is an ICP proposed originally as a negative ion source, is driven under confronting divergent magnetic fields (CDMFs), and functions of the CDMFs have been discussed for their use as a magnetic shutter or filter 11) for plasma confinement and modulation to reduce the damage of materials processed.…”

“…16) It was reported that electrons under the CDMFs obtain energy near the B ECR region via a stochastic process. 11,[17][18][19] A notable feature is that the partial resonance may occur even in the region distant from the RF antenna. Although it is considered in general that magnetic field induces the magnetic cooling of the electron temperature by binding the electron motion, the partial resonance is an interesting phenomenon as a mechanism of energy supply to electrons, and it may assist the sustainment of the magnetized ICPs.…”

Elliptic vector loci of average electron velocity of electron swarm in constant-collision-frequency model gas under ac electric and dc magnetic fields crossed at arbitrary angles

“…control of the plasma size and position [12], electron connement for high plasma density [1315], and plasma modulation for uniform wide-area processing and reduction of damage [13,1517]. The electron heating in or near the plasma sheath under the Lorentz force [1820] and the partial resonance [17,21] are also interesting phenomena that may contribute to ecient power deposition to magnetized plasmas for their sustainment.…”