Mechanism of particle transport in magnetized silane plasmas

Abstract

Particle transport phenomena were investigated in silane plasmas in the presence of magnetic field B perpendicular to discharge electric field E. ¿From the experimental results, it was known that silicon particles were transported in the opposite direction of the E × B drift, and the particle density was decreased with increasing applied magnetic flux density. Theoretical calculations on particle drift show that negatively charged particles can be transported in the opposite direction of E × B drift and its drift velocity is increased with B for the present experimental conditions. Both of experimental and theoretical results suggest that transport by modified ambipolar E × B drift can eliminate particles from discharge space.

Vertically aligned dust particles under the influence of crossed electric and magnetic fields in the sheath of a radio frequency discharge

“…Thus, the electrons perform theẼ ÂB-drift and an ambipolar electric field E a arises (inẼ ÂB-direction) between the electrons and the collisional ions. 26,27 Since the dust particles have a negative charge, the electric field force F E due to the ambipolar electric field E a points in the negativeẼ ÂB-direction. On the other hand, the ions are accelerated by this ambipolar field and drift in theẼ ÂB-direction.…”

Effects of Crossed Magnetic Fields on Silicon Particles in Plasma Chemical Vapor Deposition Process

“…the discharge space The effects of a crossed magnetic field on silicon particle behavior in DC silane discharges were discussed in greater detail in our previous studies, [23][24][25][26] but we consider them from the viewpoint of both removal and suppression of formation of silicon particles here.…”

“…In order to realize film deposition by SPM without particle contamination, the particle behaviors in magnetized DC and/or AC silane discharges have been investigated using a laser light scattering (LLS) method. In our previous studies, we have obtained the following three results: (1) when a crossed magnetic field is applied, the silicon particles which are grown and saturated within the discharge space are transported in the direction opposite to the E × B drift of plasmas and the particle density within the discharge space is drastically decreased, 23,24) (2) the calculated results from an ambipolar E × B drift diffusion model agree qualitatively with the experimental ones 25) and (3) when a crossed magnetic field is applied after the discharge initiation, the appearance time of scattering light intensity by particles is delayed in comparison with the case lacking a magnetic field. 26) These results predict that the application of a crossed magnetic field is not only effective for particle removal but also causes suppression of particle formation.…”

Large-Area Uniform Surface Treatment of Polymeric Materials Using a Scanning Plasma Method

“…From the above results, it is considered that the effect of E × B drift is more effective at lower pressures because plasma transport accurs caused by the mean free path of electrons. [7][8][9] …”

“…[1][2][3][4][5][6] We have investigated the efficiency of a crossed magnetic field method, called the scanning plasma method (SPM) which involves the use of a magnetic field B perpendicular to the discharge electric field E, for the deposition of a hydrogenated amorphous silicon (a-Si:H) thin film and dynamic control of silicon particles in silane plasma chemical vapor deposition (CVD). [7][8][9][10] The aim of this study is to verify the usefulness of the SPM in the surface treatment of polymeric materials such as polyethylene terephthalate (PET) and polypropylene ber to produce homogeneous magnetic fields of 0-60 Gauss in the axial direction of the chamber. In order to generate a uniform plasma along the film width, AC discharge with frequency of f V = 60 Hz and modulated magnetic field in the form of a rectangular wave with a modulation frequency of f B = 1 Hz, obtained using a function generator, are used.…”