Observations of bi-Maxwellian and single Maxwellian electron energy distribution functions in a capacitively coupled radio-frequency plasmas by laser Thomson scattering

Abstract

Comparison of atmospheric-pressure helium and argon plasmas generated by capacitively coupled radiofrequency discharge Phys. Plasmas 13, 093503 (2006); 10.1063/1.2355428 Time evolution of ion energy distributions and optical emission in pulsed inductively coupled radio frequency plasmas A study of electron energy distributions in an inductively coupled plasma by laser Thomson scattering

Measurements of Electron Energy Probability Functions in inductively coupled plasma with laser Thomson scattering

“…The ∆λ 2 referenced from the wavelength of incidence laser light (532 nm) is proportional to the electron energy, this spectrum is corresponding to EEPF as explained before, thus we can compared it with the result Langmuir probe EEPF (figure 6 (b)). Indeed, our Thomson spectrum signal of figure 6 (a) is well recognized as a Maxwellian distribution which is typical one in ICP discharge, with clear straight line slope, high signal to noise ratio, and little distortion compared with other previous results [3][4][5]9]. As the discharge power increases, the level of EEPF increase with a little increase of slop in EEPF, ie, while increasing the discharge power, the electron density increases and the electron temperature deceases a little (see figure 7).…”

“…Although it is hard to measure plasma parameters in processing plasma due to using molecular species for processing gases that cause Raman scattering which makes signals distorted, its low electron density, low electron temperature and small cross section of electron itself, many researches have been performed on various plasma sources and conditions. Starting from the first measurement in Electron Cyclotron Resonance (ECR) plasma of low temperature plasma sources performed by M. Bowden, et al [3], many studies on the sources of Inductively Coupled Plasma (ICP) [4], Capacitively Coupled Plasma (CCP) [5], Magnetized Inductively Coupled Plasma (MICP) [6] and others [7][8][9] have been performed for measurements of EEPFs. Those results normally showed a typical maxwellian distribution [3,4,[6][7][8][9] or a bimaxwellian distribution [4,5,10] in high pressure or low pressure respectively, and its transition via pressure change, which is consistent with the result of probe EEPFs diagnostics [11].…”

“…Starting from the first measurement in Electron Cyclotron Resonance (ECR) plasma of low temperature plasma sources performed by M. Bowden, et al [3], many studies on the sources of Inductively Coupled Plasma (ICP) [4], Capacitively Coupled Plasma (CCP) [5], Magnetized Inductively Coupled Plasma (MICP) [6] and others [7][8][9] have been performed for measurements of EEPFs. Those results normally showed a typical maxwellian distribution [3,4,[6][7][8][9] or a bimaxwellian distribution [4,5,10] in high pressure or low pressure respectively, and its transition via pressure change, which is consistent with the result of probe EEPFs diagnostics [11]. Some of the researches have been performed to compare the LTS result with the Single Langmuir Probe (SLP) result [11,12,[12][13][14], and a research of more reliable LTS EEPFs diagnostics including a comparative result with SLP EEPFs is still needed not only to establish the reliable LTS EEPF diagnostic but also to support the uncertainty and accuracy for the SLP.…”

Analysis of uncertainty of electron density and temperature using laser Thomson scattering in helicon plasmas

“…[1][2][3][4][5][6][7][8] Among the diagnostic methods, the laser Thomson scattering (TS) method is believed to be a promising diagnostic method as a standard of the low temperature plasma metrology, because its basic measurement principle is very simple and it is not affected by the noises from plasma source (RF noise, magnetic field noise, and so on). 1,9,10) Although the laser Thomson Scattering method has been known for its high measurement accuracy, [11][12][13][14][15][16][17][18][19] there can be also large uncertainty in plasma parameter measurements depending on the input quantities in the measurement model such as a scattering signal or a stray light signal. Therefore, analysis of uncertainty for the input quantities and ultimately the measurand is needed.…”

Fast measurement of a pulsed plasma using a Fourier cutoff probe

“…In addition, it cannot be used in processing plasmas because of a tip deposition problem. [4] Microwave interferometers [5,6] and Thompson scattering [7][8][9] meanwhile require a heavy and bulky system, and hence are not suitable for processing plasmas. However, microwave probes, such as a hairpin probe, [10] a plasma absorption probe, [11] or a cutoff probe, [4,12] have many advantages for processing plasmas: (i) simple structures; (ii) measurement of local plasma characteristics; and (iii) insensitivity to processing plasmas used in deposition and etching.…”