Optical emission characteristics and mode transitions in low-frequency inductively coupled plasmas

Abstract

Optical emission characteristics of the 500 kHz flat-coil inductively coupled discharges in pure argon, nitrogen, and gas mixtures of Ar+H2, N2+Ar, and N2+H2 are investigated. Variation of input power and operating gas pressure lead to hysteresis in the optical emission intensity (OEI), which is associated with the transitions between the electrostatic (E) and electromagnetic (H) discharge operating regimes. The characteristics of the hysteresis loops and character of mode transitions appear to be different in pure gases and gas mixtures. It has been observed that the E→H transition are always discontinuous, while the H→E transitions appear smooth in pure nitrogen and N2-dominated discharges. Dependence of the E→H transition threshold on gas composition in Ar+N2, Ar+H2, and N2+H2 mixtures is investigated and underlying mechanisms are discussed. It is also shown that the OEI of nitrogen species can efficiently be controlled by small Ar or H2 admixtures. Addition of argon enhances the optical emission of N2, N2+, N, and N+ species, whereas the effect of hydrogen admixture is the opposite.

Inductively coupled plasma-assisted RF magnetron sputtering deposition of boron-doped microcrystalline Si films

“…This non-capacitive power transfer is effective in reducing plasma sheath potentials at wall surfaces, electrodes and substrates, and therefore diminishes the bombarding energy of the ions impinging on the growth surface [18,27,28]. It also provides an independent control of the ion/radical fluxes and ion-bombarding energy.…”

“…Moreover, the inductively coupled plasma source features high-densities of electrons and ions. The typical plasma density achieved in the ICP discharge is about a factor of 10-100 times higher than those produced by capacitive discharges under quite similar conditions [18,27,28]. As such, ICP-enhanced chemical vapor deposition has attracted a great deal of interest for low-pressure, low-temperature material processing [9,18,29,30].…”

Nonlinear electromagnetic fields in 0.5 MHz inductively coupled plasmas

“…Electronic mail: kostrikov@nie.edu.sg plasma parameters over large areas and volumes, and several others. [12][13][14] Hence, at low frequencies, one should expect significant distortions of the electromagnetic field/current patterns, which can be due to the generation of nonlinear signals at higher Fourier harmonics or static nonlinear ͑ponderomo-tive͒ responses. Hysteretic effects in mode transition phenomena is yet another intrinsically nonlinear feature of inductively coupled plasmas.…”

Customizing electron confinement in plasma-assembled Si/AlN nanodots for solar cell applications

“…This noncapacitive power transfer in turn leads to low plasma sheath potentials in the vicinity of the electrode, substrate, and wall surfaces. [27][28][29] As such, the ICP source is capable of generating thermally nonequilibrium ͑temperatures of electrons T e , ions T i , and neutrals T n satisfy T e ӷ T i ϳ T n ͒, high-density plasmas at low operating pressures; the achievable electron/ion number densities ͑typically up to ϳ10 12 cm −3 at moderate input power densities͒ can be 1-2 orders of magnitude higher than in conventional capacitive discharges operated under similar conditions. 27 Under such conditions, the near-surface potential drop does not usually exceed a couple of ten volts.…”