Electron Cyclotron Resonance Discharge Plasma Research Articles

Measurement of linear polarization in the HeI 21P–31D emission line in an electron cyclotron resonance discharge plasma

The magnitude and direction of linear polarization in the HeI 21P–31D emission line are simultaneously measured using a beam-splitting-type polarization spectroscopy system. The polarization measured in the steady-state phase of an electron cyclotron resonance (ECR) discharge produced in a simple cusp field is directed closely perpendicular to the magnetic field at the ECR surface, and the degree of polarization increases up to 8% when the neutral pressure is reduced to less than 23 mPa. These results suggest that the cause of the polarization is attributable to impact excitation by high-energy electrons produced at the ECR surface.

Pulse-Periodic Regime of Kinetic Instability of the ECR Discharge Plasma Under the Conditions of Double Plasma Resonance

UDC 533.9.01 We study the stability of a dense nonequilibrium plasma of the electron cyclotron resonance (ECR) discharge in an open magnetic trap immediately after the end of heating. The observed instability is accompanied by pulse-periodic generation of high-power electromagnetic radiation at a frequency that is close to the frequency of the upper hybrid resonance and the double gyrofrequency of electrons and by synchronous precipitations of fast electrons from the trap. It is shown that the observed instability is connected with excitation of plasma waves under the conditions of double plasma resonance in the decaying plasma of the ECR discharge.

Towards 0.99999 28Si

A new approach for producing high-purity silicon with isotopic enrichment of 28Si isotope is reported. The methods of centrifugal enrichment were modified to obtain the initial gaseous silicon tetrafluoride with a record-breaking enrichment of 0.99999664(11) with respect to 28Si. The effective conversion of silicon tetrafluoride into elementary silicon with minimal isotopic dilution was achieved in an electron cyclotron resonance discharge plasma, sustained by gyrotron microwave radiation with a frequency of 24 GHz. We have experimentally demonstrated the deposition of the layers of microcrystalline 28Si with enrichment of 0.999986 ± 0.000003, which is the best result at the present time.

Experimental investigations of silicon tetrafluoride decomposition in ECR discharge plasma

The results of first experiments on the investigation of plasma of electron cyclotron resonance (ECR) discharge, sustained by CW radiation of technological gyrotron with frequency 24 GHz are considered. The parameters of nitrogen plasma of ECR discharge in magnetic field up to 1 T were investigated by Langmuir probe in the pressure range 10(-4)-10(-2) mbar under different values of microwave power. Depending on gas pressure and power of microwave radiation, the typical temperature and density of electrons could attain values of 1-5 eV and 10(11)-10(12) cm(-3), respectively. The prospects for using of ECR discharge for plasma chemical decomposition of silicon tetrafluoride (SiF(4)) have been experimentally demonstrated. Plasma was created from SiF(4) and hydrogen (H(2)) gas mixture and heated by microwave radiation in ECR conditions. Using the method of mass-spectrometry analysis of the gas at the outlet from the reactor and the weighting method, the content of the resultants of SiF(4) decomposition as a function of process parameters was investigated. It was shown that SiF(4) decomposition degree strongly depends on the microwave power, gas pressure in the reactor, gas flow rates, and can attain the value of 50%. The possible applications of PECVD method based on ECR discharge for production of isotopically pure elements with high deposition rate are discussed.

Intermediate Gas Phase of CH4/[Si(CH3)2O]5 Plasma and Its Effect on Structure of SiCOH Film

This paper investigated the radical behaviour of the plasma of a mixture of methane (CH4) and decamethylcyclopentasiloxane (DMCPS) by optical emission spectroscopy. The plasma was generated by electron cyclotron resonance (ECR) discharge and was used for depositing porous SiCOH low dielectric-constant film. In the ECR discharge plasma, CH, H, H2, C2, Si, O and SiO radicals were obtained. The CH, H and C2 radicals were from the dissociation of CH4, while the SiO, Si and O radicals from the dissociation of the Si-O chain. CHx radicals absorbed in the film were thermally unstable and could be removed by annealing. The dissociation of the Si-O chain led to an increase in a ratio of the Si-Ocage to Si-Onetwork. The removed of CHx radicals and the increased Si-Ocage to Si-Onetwork ratio were beneficial for reducing the film density and dielectric constant.

Mass Spectrometry Investigation on Decamethylcyclopentasiloxane Electron Cyclotron Resonance Plasma for SiCOH Film Deposition

We investigate the fragmentation behaviour of decamethylcyclopentasiloxane (DMCPS) plasma using a quadrupole mass spectrometry, which is used as the precursor to deposit SiCOH film in an electron cyclotron resonance (ECR) plasma system. The structure of DMCPS molecules comprises a fivefold Si-O ring and ten -CH3 groups bonded at five Si atoms. In ECR discharge plasma, the main fragmentation behaviour of DMCPS includes two stages. One is the breaking of fivefold Si-O rings and then the formation of threefold Si-O rings and Si-O chain species. The other is the decomposing of hydrocarbon groups from Si atoms and then the crosslink of hydrocarbon species. Combined with the bonding configuration of SiCOH films, the relation between species in ECR plasma and films structures is analysed.

Temperature-dependent dry cleaning characteristics of GaAs (111)B surfaces with a hydrogen electron cyclotron resonance plasma

The cleaning of the GaAs (111)B surface with a hydrogen electron cyclotron resonance discharge plasma is investigated at temperatures between 200 and 500 °C and compared with the GaAs (100) surface. It is found that during the exposure the GaAs (111)B is etched in a non-Arrhenius way with a higher etch rate at low temperatures. For temperatures 300–500 °C, the surface is severely roughened after exposure, while the (100) surface remains smooth in all cases. The near-surface crystalline quality of GaAs (111)B remains higher than that of (100).

Particle loss from an electron cyclotron resonance discharge plasma in the WT-2 device

The dominant particle loss from an electron cyclotron resonance discharge plasma in a simple toroidal configuration is ascribed to the E × B drift due to the vertical electric field produced by the electrons' toroidal drift. The electron density is increased by adding a small vertical field. This is explained by the electron flow along the line of force canceling the toroidal drift, resulting in reduction of the E × B drift.