A computational investigation of the RF plasma structures and their production efficiency in the frequency range from HF to VHF

Abstract

The influence of driving frequency on discharge structure and production efficiency has been investigated in Ar over the frequency range from 13.56MHz to l00MHz in terms of the relaxation continuum model. Under constant RF voltage, the plasma density increases in proportion to the square of the driving frequency. The net ionization and excitation rates, and the power density, show the same frequency dependence, although the collisional production efficiency per input power density is almost invariant with change of frequency. This has the great advantage for plasma processing and deposition from plasmas that parallel plate discharge in vety high frequency (VHF) will lead to the system being rather free from ion damage or effects of confined plasma volume as compared with those in high frequency (HF) and microwave (MW).

Charged Particle Transport in Harmonically Varying Electric Fields: Foundations and Phenomenology

“…{0 but R=0. Then, under the combined operations (10), the nonlinear system (1), (3), (4), (5) is form invariant, and we deduce that…”

“…plasmas the space-charge field is strong, especially in the sheath regions near the boundaries, and the full moment equations of Section 4 must be solved simultaneously with Poisson's equation (4). Neither can it generally be assumed that spatial variations are weak and therefore gradients of properties in the moment equations cannot be treated using the simplifying assumptions of the hydrodynamic regime and associated density gradient expansions.…”

“…It is not necessary (nor desirable) to make further approximations to the ion moment equations of Section 4(ii), e.g., to assume the hydrodynamic approximation for ions and to represented fluxes etc., in terms of hydrodynamic transport coefficients. A far more satisfactory procedure would be to solve the moment equations for ions and electrons together as is, in conjunction of course with Poisson's equation (4). This remark is made independently of how the d.c. swarm data is to be incorporated, either through the implicity functional dependence upon energy or through an empirical effective d.c. field E*.…”

Predictive study of a plasma structure and function in reactive ion etcher driven by very high frequency: Validity of an extended two-dimensional relaxation continuum model

“…24,25 The VHF power supply direct to the substrate will be limited to ϳ100 MHz due to a technological difficulty in keeping a radial uniformity of the surface potential while increasing the frequency. Plasma driven by a frequency of more than several hundred MHz will be, therefore, maintained by the aid of several types of antennas.…”

Effect of the Driving Frequency on the Emission Characteristics of a Radio-frequency Glow Discharge Excitation Source Boosted by the Introduction of a D. C. Bias Current

“…Though conventional GDPs for spectrometric analysis have usually been operated at a driving frequency of 13.56 MHz, 11 several investigations using various frequencies have reported that the supplied frequency had a pronounced influence on the properties of the r.f.-GDP employed in sputter etching or surface treatment technologies. 14,15 Also in r.f.-GD-OES, Lazik and Marcus, 16 and Heintz and Hieftje 17 have demonstrated the influence of the driving frequency on several characteristics of the r.f.-GD-OES such as the sampling rate and the emission intensities, indicating that the driving frequency could affect such properties greatly and should be optimized for a particular application of the r.f.-GDP device. Matsuta et al reported on the unique properties of a 40.68-MHz r.f.…”