An experimental investigation of the argon plasma behavior near the E–H transition in an inductively coupled Gaseous Electronics Conference reference cell is reported. Electron density and temperature, ion density, argon metastable density, and optical emission measurements have been made as function of input power and gas pressure. When plotted versus plasma power, applied power corrected for coil and hardware losses, no hysteresis is observed in the measured plasma parameter dependence at the E–H mode transition. This suggests that hysteresis in the E–H mode transition is due to ignoring inherent power loss, primarily in the matching system.

Optical emission spectroscopy as a noninvasive plasma diagnostic was employed to study mode transitions and hysteresis in an inductively coupled plasma in Ar and Ar/ N 2 mixtures. Using selected Ar lines, basic plasma parameters, relevant to the analysis of the mode transitions, were evaluated. Small changes of the electron energy distribution function in the vicinity of the mode transition were detected. The role of metastable Ar atoms in mode transitions and in a hysteresis was clarified. Enhanced production of metastables in the hysteresis region as well as faster transitions in plasmas with higher influence of metastables were observed.

Articles you may be interested inOptimization of in situ plasma oxidation of metallic gadolinium thin films deposited by high pressure sputtering on silicon J. Vac. Sci. Technol. B 31, 01A112 (2013); 10.1116/1.4769893 Role of chamber dimension in fluorocarbon based deposition and etching of Si O 2 and its effects on gas and surface-phase chemistry J. Vac. Sci. Technol. A 26, 545 (2008); 10.1116/1.2909963Effect of N 2 O plasma treatment on the stabilization of water absorption in fluorinated silicon-oxide thin films fabricated by electron-cyclotron-resonance plasma-enhanced chemical-vapor deposition Electron cyclotron resonance plasmas with SiH 4 /O 2 / Ar mixtures were used for deposition of thin films of silicon oxide, to be employed as sacrificial layers in microelectromechanical system ͑MEMS͒ fabrication. The grown films were characterized by Fourier transform infrared and ellipsometry. Optical emission spectroscopy and Langmuir probe were used for plasma characterization. It has been shown that OH molecules generated in the plasma play an important role in formation of films suitable as sacrificial layers for MEMS fabrication. Extremely high etch rates of grown oxide films ͑up to 10 m / min͒ were obtained, allowing fabrication of high quality poly-Si suspended structures.

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A new modified branching ratio (MBR) method for the absolute intensity calibration of a vacuum ultraviolet (VUV) spectrometer is presented. The spectrometer is equipped with a multichannel detector, consisting of an open microchannel plate coupled to a charge-coupled device (CCD), or with a single channel photomultiplier. This technique extends the number of calibration points available from those provided by the branching ratio (BR) calibration technique. The MBR method is a variation of the conventional BR method, where we relax the condition that the two spectral emissions, in the visible and VUV spectra, come from the same excited level, to include transitions from different sublevels of the same energy level. However, a critical study of the statistical equilibrium of sublevels from the same ion energy level was necessary. As a result, we have more than doubled the number of calibration points for our spectrometer used in tokamak plasma diagnostics. The appropriate identification of new spectral line pairs for absolute calibration here presented opens the path for future works in other devices with similar plasma conditions or impurities content.