The IR emission spectra of methane were measured under DC glow discharge conditions. The distinct difference in time between methane decomposition and C2 hydrocarbons formation was specially pointed out. C2 hydrocarbo...The IR emission spectra of methane were measured under DC glow discharge conditions. The distinct difference in time between methane decomposition and C2 hydrocarbons formation was specially pointed out. C2 hydrocarbons formed at the end of methane decomposition. The optimum condition for C2 hydrocarbon formation was studied and the optimum combination between electric current density and methane input quantity was suggested. The appropriate reaction conditions for methane decomposition and C2 hydrocarbons formation are different, so high yield of C2 hydrocarbons will be probably obtained when different conditions are taken.展开更多
Fluorinated amorphous carbon (a-C: F, H) films were deposited by inductively coupled plasma using CH4 and CF4 gases. Actinometrical optical emission spectroscopy (AOES) was used to determine the relative concentration...Fluorinated amorphous carbon (a-C: F, H) films were deposited by inductively coupled plasma using CH4 and CF4 gases. Actinometrical optical emission spectroscopy (AOES) was used to determine the relative concentrations of various radicals, CF, CF2 CH, C2, H and F, in the plasma as a function of gas flow ratio R, R = [CH4]/([CH4]+[CF4]). The structural evolution of the films were characterized by Fourier transform infrared transmission (FTIR) spectroscopy. The relationship between the film deposition and the precursor radicals in the plasma was discussed.It was shown that CH radical, as well as CF, CF2, C2 radicals are of the precursors, contributing to a-C: F, H film growth.展开更多
The ion line of 434.8 nm and atom line of 419.8 nm of Ar plasma produced byan inductively coupled plasma (ICP) were measured by optical emission spectroscopy and theinfluences from the working gas pressure,radio-frequ...The ion line of 434.8 nm and atom line of 419.8 nm of Ar plasma produced byan inductively coupled plasma (ICP) were measured by optical emission spectroscopy and theinfluences from the working gas pressure,radio-frequency (RF) power and different positions inthe discharge chamber on the line intensities were investigated in this study.It was found that theintensity of Ar atom line increased firstly and then saturated with the increase of the pressure.Theline intensity of Ar^+,on the other hand,reached a maximum value and then decreased along withthe pressure.The intensity of the line in an RF discharge also demonstrated a jumping mode and ahysteresis phenomenon with the RF power.When the RF power increased to 400 W,the dischargejumped from the E-mode to the H-mode where the line intensity of Ar atom demonstrated a suddenincrease,while the intensity of Ar+ ion only changed slightly.If the RF power decreased from ahigh value,e.g.,1000 W,the discharge would jump from the H-mode back to the E-mode at apower of 300 W.At this time the intensities of Ar and Ar+ lines would also decrease sharply.Itwas also noticed in this paper that the intensity of the ion line depended on the detective locationin the chamber,namely at the bottom of the chamber the line was more intense than that in themiddle of the chamber,but less intense than at the top,which is considered to be related to thecapacitance coupling ability of the ICP plasma in different discharge areas.展开更多
A method to determine excitation temperatures based on the optical emission spec-troscopy(OES)and Fermi-Dirac distribution was set up,and the temperatures of pure-argonand mixed-gases at different pressures were inves...A method to determine excitation temperatures based on the optical emission spec-troscopy(OES)and Fermi-Dirac distribution was set up,and the temperatures of pure-argonand mixed-gases at different pressures were investigated.In this way we set up a standard pro-cess to get the excitation temperatures of plasmas operated at atmospheric and展开更多
In order to deposit good films,we need to study the uniformity of plasma density andthe plasma density under different gas pressures and powers.The plasma density was diagnosedby a Langmuir probe.The optical emission ...In order to deposit good films,we need to study the uniformity of plasma density andthe plasma density under different gas pressures and powers.The plasma density was diagnosedby a Langmuir probe.The optical emission spectroscopy(OES)of CH_4 and H_2 discharge wasobtained with raster spectroscopy,with characteristic peaks of H and CH achieved.Diamond-likecarbon films were achieved based on the study of plasma density and OES and characterized byatomic force microscope(AFM),X-ray diffraction instrument(XRD),Raman spectroscope andprofiler.展开更多
This paper investigated the radical behaviour of the plasma of a mixture of methane (CH_4)and decamethylcyclopentasiloxane(DMCPS)by optical emission spectroscopy.The plasma was generated by electron cyclotron resonanc...This paper investigated the radical behaviour of the plasma of a mixture of methane (CH_4)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,H_2,C_2,Si,0 and SiO radicals were obtained.The CH,H and C_2 radicals were from the dissociation of CH_4,while the SiO,Si and O radicals from the dissociation of the Si-O chain.CH_x 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-O_(cage)to Si-O_(network).The removed of CH_x radicals and the increased Si-O_(cage)to Si-O_(network)ratio were beneficial for reducing the film density and dielectric constant.展开更多
Optical emission from TiO_2 plasma,generated by a nanosecond laser is spectroscop-ically analysed.The main chemical species are identified and the spatio-temporal distribution ofthe plasma parameters such as electron ...Optical emission from TiO_2 plasma,generated by a nanosecond laser is spectroscop-ically analysed.The main chemical species are identified and the spatio-temporal distribution ofthe plasma parameters such as electron temperature and density are characterized based on thestudy of spectral distribution of the line intensities and their broadening characteristics.The pa-rameters of laser induced plasma vary quickly owing to its expansion at low background pressureand the possible deviations from local thermodynamic equilibrium conditions are tested to showits validity.展开更多
基金Supported by the Special Fund of the Education Committee of Shaanxi Province (No. 2000K13-G19 and No. 2002K09-G21).
文摘The IR emission spectra of methane were measured under DC glow discharge conditions. The distinct difference in time between methane decomposition and C2 hydrocarbons formation was specially pointed out. C2 hydrocarbons formed at the end of methane decomposition. The optimum condition for C2 hydrocarbon formation was studied and the optimum combination between electric current density and methane input quantity was suggested. The appropriate reaction conditions for methane decomposition and C2 hydrocarbons formation are different, so high yield of C2 hydrocarbons will be probably obtained when different conditions are taken.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10575027 and 10647123）, the National Science Foundation of Hebei Province, China （Grant No A2007000134）, the Education Department of Hebei Province, China （Grant No 2006106）, and the Natural Science Foundation of Hebei University （Grant No 2006061）.
文摘Fluorinated amorphous carbon (a-C: F, H) films were deposited by inductively coupled plasma using CH4 and CF4 gases. Actinometrical optical emission spectroscopy (AOES) was used to determine the relative concentrations of various radicals, CF, CF2 CH, C2, H and F, in the plasma as a function of gas flow ratio R, R = [CH4]/([CH4]+[CF4]). The structural evolution of the films were characterized by Fourier transform infrared transmission (FTIR) spectroscopy. The relationship between the film deposition and the precursor radicals in the plasma was discussed.It was shown that CH radical, as well as CF, CF2, C2 radicals are of the precursors, contributing to a-C: F, H film growth.
基金supported by National Natural Science Foundation of China (Nos.50277003,10505005)
文摘The ion line of 434.8 nm and atom line of 419.8 nm of Ar plasma produced byan inductively coupled plasma (ICP) were measured by optical emission spectroscopy and theinfluences from the working gas pressure,radio-frequency (RF) power and different positions inthe discharge chamber on the line intensities were investigated in this study.It was found that theintensity of Ar atom line increased firstly and then saturated with the increase of the pressure.Theline intensity of Ar^+,on the other hand,reached a maximum value and then decreased along withthe pressure.The intensity of the line in an RF discharge also demonstrated a jumping mode and ahysteresis phenomenon with the RF power.When the RF power increased to 400 W,the dischargejumped from the E-mode to the H-mode where the line intensity of Ar atom demonstrated a suddenincrease,while the intensity of Ar+ ion only changed slightly.If the RF power decreased from ahigh value,e.g.,1000 W,the discharge would jump from the H-mode back to the E-mode at apower of 300 W.At this time the intensities of Ar and Ar+ lines would also decrease sharply.Itwas also noticed in this paper that the intensity of the ion line depended on the detective locationin the chamber,namely at the bottom of the chamber the line was more intense than that in themiddle of the chamber,but less intense than at the top,which is considered to be related to thecapacitance coupling ability of the ICP plasma in different discharge areas.
文摘A method to determine excitation temperatures based on the optical emission spec-troscopy(OES)and Fermi-Dirac distribution was set up,and the temperatures of pure-argonand mixed-gases at different pressures were investigated.In this way we set up a standard pro-cess to get the excitation temperatures of plasmas operated at atmospheric and
基金supported in part by the National Natural Science Foundation of China （10575039） the Chinese Specialized Research Fund for the Doctoral Programme of Higher Education （2004057408）+1 种基金the Key Project of Science Research Fund of Guangdong （China） （05100534）the Science Project Foundation of Guangzhou City （China） （2005Z3-D2031）.
文摘In order to deposit good films,we need to study the uniformity of plasma density andthe plasma density under different gas pressures and powers.The plasma density was diagnosedby a Langmuir probe.The optical emission spectroscopy(OES)of CH_4 and H_2 discharge wasobtained with raster spectroscopy,with characteristic peaks of H and CH achieved.Diamond-likecarbon films were achieved based on the study of plasma density and OES and characterized byatomic force microscope(AFM),X-ray diffraction instrument(XRD),Raman spectroscope andprofiler.
基金National Natural Science Foundation of China(Nos.10575074,10635010)
文摘This paper investigated the radical behaviour of the plasma of a mixture of methane (CH_4)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,H_2,C_2,Si,0 and SiO radicals were obtained.The CH,H and C_2 radicals were from the dissociation of CH_4,while the SiO,Si and O radicals from the dissociation of the Si-O chain.CH_x 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-O_(cage)to Si-O_(network).The removed of CH_x radicals and the increased Si-O_(cage)to Si-O_(network)ratio were beneficial for reducing the film density and dielectric constant.
文摘Optical emission from TiO_2 plasma,generated by a nanosecond laser is spectroscop-ically analysed.The main chemical species are identified and the spatio-temporal distribution ofthe plasma parameters such as electron temperature and density are characterized based on thestudy of spectral distribution of the line intensities and their broadening characteristics.The pa-rameters of laser induced plasma vary quickly owing to its expansion at low background pressureand the possible deviations from local thermodynamic equilibrium conditions are tested to showits validity.
