Enhancing plasma uniformity can be achieved by modifying coil and chamber structures in radio frequency inductively coupled plasma(ICP)to meet the demand for large-area and uniformly distributed plasma in industrial m...Enhancing plasma uniformity can be achieved by modifying coil and chamber structures in radio frequency inductively coupled plasma(ICP)to meet the demand for large-area and uniformly distributed plasma in industrial manufacturing.This study utilized a two-dimensional self-consistent fluid model to investigate how different coil configurations and chamber aspect ratios affect the radial uniformity of plasma in radio frequency ICP.The findings indicate that optimizing the radial spacing of the coil enhances plasma uniformity but with a reduction in electron density.Furthermore,optimizing the coil within the ICP reactor,using the interior point method in the Interior Point Optimizer significantly enhances plasma uniformity,elevating it from 56%to 96%within the range of the model sizes.Additionally,when the chamber aspect ratio k changes from 2.8 to 4.7,the plasma distribution changes from a center-high to a saddleshaped distribution.Moreover,the plasma uniformity becomes worse.Finally,adjusting process parameters,such as increasing source power and gas pressure,can enhance plasma uniformity.These findings contribute to optimizing the etching process by improving plasma radial uniformity.展开更多
To maintain the high-density plasma source in inductively coupled plasma(ICP),very high radiofrequency power is often delivered to the antenna,which can heat the dielectric windows near the antenna to high temperature...To maintain the high-density plasma source in inductively coupled plasma(ICP),very high radiofrequency power is often delivered to the antenna,which can heat the dielectric windows near the antenna to high temperature.This high temperature can modulate the plasma characteristics to a large degree.We thus study the effect of dielectric window temperature on plasma parameters in two different ICP structures based on COMSOL software.The distributions of various plasma species are examined at different dielectric window temperatures.The concentration of neutral gas is found to be largely modulated at high dielectric window temperature,which further affects the electron collision probability with neutrals and the electron temperature.However,the electron density profiles are barely affected by the dielectric window temperature,which is mainly concentrated at the center of the reactor due to the fixed power input and pressure.展开更多
In this work,a two-dimensional hybrid model,which consists of a bulk fluid module,a sheath module and an ion Monte-Carlo module,is developed to investigate the modulation of ion energy and angular distributions at dif...In this work,a two-dimensional hybrid model,which consists of a bulk fluid module,a sheath module and an ion Monte-Carlo module,is developed to investigate the modulation of ion energy and angular distributions at different radial positions in a biased argon inductively coupled plasma.The results indicate that when the bias voltage amplitude increases or the bias frequency decreases,the ion energy peak separation width becomes wider.Besides,the widths of the ion energy peaks at the edge of the substrate are smaller than those at the center due to the lower plasma density there,indicating the nonuniformity of the ion energy distribution function(IEDF)along the radial direction.As the pressure increases from 1 to 10 Pa,the discrepancy of the IEDFs at different radial positions becomes more obvious,i.e.the IEDF at the radial edge is characterized by multiple low energy peaks.When a dual frequency bias source is applied,the IEDF exhibits three or four peaks,and it could be modulated efficiently by the relative phase between the two bias frequencies.The results obtained in this work could help to improve the radial uniformity of the IEDF and thus the etching process.展开更多
A An analytical method using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of 24 elements (Be, Mg, A1, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, ...A An analytical method using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of 24 elements (Be, Mg, A1, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn Sb, Ba, Pt, Au, and Pb) in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCI. The matrix effects because of the presence of excess HCI and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination were tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits were 0.016-1.50 ].tg·g^-1, the recovery ratios were 92.2%-111.2%, and the RSD was less than 3.6%. The method was accurate, quick, and convenient. It was applied to the determination of trace impurities in high purity cobalt with satisfactory results.展开更多
A study of Cl2/BCl3-based inductively coupled plasma (ICP) was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etc...A study of Cl2/BCl3-based inductively coupled plasma (ICP) was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etching depths of more than 150μm. Plasma etch characteristics with ICP process pressure and the percentage of BCI3 were studied in greater detail at a constant ICP coil/bias power. The measured peak-to-peak voltage as a function of pressure was used to estimate the minimum energy of the ions bombarding the substrate. The process pressure was found to have a substantial influence on the energy of heavy ions. Various ion species in plasma showed minimum energy variation from 1.85 eV to 7.5 eV in the pressure range of 20 mTorr to 50 mTorr. The effect of pressure and the percentage of BCl3 on the etching rate and surface smoothness of the bottom surface of the etched hole were studied for a fixed total flow rate. The etching rate was found to decrease with the percentage of BCl3, whereas the addition of BCl3 resulted in anisotropic holes with a smooth veil free bottom surface at a pressure of 30 mTorr and 42% BC13. In addition, variation of the etching yield with pressure and etching depth were also investigated.展开更多
ZrN fihns were deposited on Si(111) and M2 steel by inductively coupled plasma (ICP)-enhanced RF magnetron sputtering. The effect of ICP power on the microstructure, mechanical properties and corrosion resistance ...ZrN fihns were deposited on Si(111) and M2 steel by inductively coupled plasma (ICP)-enhanced RF magnetron sputtering. The effect of ICP power on the microstructure, mechanical properties and corrosion resistance of ZrN films was investigated. When the ICP power is below 300 W, the ZrN films show a columnar structure. With the increase of ICP power, the texture coefficient (To) of the (111) plane, the nanohardness and elastic modulus of the films increase and reach the maximum at a power of 300 W. As the ICP Power exceeds 300 W, the films exhibit a ZrN and ZrNx mixed crystal structure without columnar grain while the nanohardness and elastic modulus of the films decrease. All the ZrN coated samples show a higher corrosion resistance than that of the bare M2 steel substrate in 3.5% NaCl electrolyte. The nanohardness and elastic modulus mostly depend on the crystalline structure and Tc of ZrN(111).展开更多
The geometry of an inductively coupled plasma (ICP) etcher is usually considered to be an important factor for determining both plasma and process uniformity over a large wafer. During the past few decades, these pa...The geometry of an inductively coupled plasma (ICP) etcher is usually considered to be an important factor for determining both plasma and process uniformity over a large wafer. During the past few decades, these parameters were determined by the "trial and error" method, resulting in wastes of time and funds. In this paper, a new approach of regression orthogonal design with plasma simulation experiments is proposed to investigate the sensitivity of the structural parameters on the uniformity of plasma characteristics. The tool for simulating plasma is CFD-ACE+, which is commercial multi-physical modeling software that has been proven to be accurate for plasma simulation. The simulated experimental results are analyzed to get a regression equation on three structural parameters. Through this equation, engineers can compute the uniformity of the electron number density rapidly without modeling by CFD-ACE+. An optimization performed at the end produces good results.展开更多
The ion density distribution in the reaction chamber was diagnosed by a Langmuir probe. The rules of the ion density distribution were obtained under the pressures of 9 Pa, 13 Pa, 27 Pa and 53 Pa in the reaction chamb...The ion density distribution in the reaction chamber was diagnosed by a Langmuir probe. The rules of the ion density distribution were obtained under the pressures of 9 Pa, 13 Pa, 27 Pa and 53 Pa in the reaction chamber, different radio-frequency powers and different positions. The result indicates that the ion density decreases as the pressure increases, and increases as the power decreases. The ion density of axial position z =0 achieves 5.8×1010 on the center of coil under the power of 200 w and pressure of 9 Pa in the reaction chamber.展开更多
An analytical method using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of Be, Mg, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn, ...An analytical method using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of Be, Mg, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn, Sb, Ba, Pt, Au and Pb in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCl. The matrix effects due to the presence of excess HCl and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination was tested and discussed. Correction for matrix effects, Sc, Rh and Bi were used as internal standards. The detection limits is 0.003-0.57 μg/g, the recovery ratio is 92.2%-111.2%, and the RSD is less than 3.6%. The method is accurate, quick and convenient. It has been applied to the determination of trace impurities in high purity cobalt with satisfactory results.展开更多
An improved analytical method to determine the content of 52 major, minor and trace elements in marine geological samples, using a HF-HCl-HNO_3 acid system with a high-pressure closed digestion method(HPCD), is stud...An improved analytical method to determine the content of 52 major, minor and trace elements in marine geological samples, using a HF-HCl-HNO_3 acid system with a high-pressure closed digestion method(HPCD), is studied by an inductively coupled plasma optical emission spectrometry(ICP-OES) and an inductively coupled plasma mass spectrometry(ICP-MS). The operating parameters of the instruments are optimized, and the optimal analytical parameters are determined. The influences of optical spectrum and mass spectrum interferences, digestion methods and acid systems on the analytical results are investigated. The optimal spectral lines and isotopes are chosen, and internal standard element of rhodium is selected to compensate for matrix effects and analytical signals drifting. Compared with the methods of an electric heating plate digestion and a microwave digestion, a high-pressure closed digestion method is optimized with less acid, complete digestion,less damage for digestion process. The marine geological samples are dissolved completely by a HF-HCl-HNO_3 system, the relative error(RE) for the analytical results are all less than 6.0%. The method detection limits are 2–40μg/g by the ICP-OES, and 6–80 ng/g by ICP-MS. The methods are used to determine the marine sediment reference materials(GBW07309, GBW07311, GBW07313), rock reference materials(GBW07103, GBW07104,GBW07105), and cobalt-rich crust reference materials(GBW07337, GBW07338, GBW07339), the obtained analytical results are in agreement with the certified values, and both of the relative standard deviation(RSD) and the relative error(RE) are less than 6.0%. The analytical method meets the requirements for determining 52 elements contents of bulk marine geological samples.展开更多
An investigation was made into polystyrene (PS) grafted onto nanometre silicon carbide (SIC) particles. In our experiment, the grafting polymerization reaction was induced by a radio frequency (RF) inductively c...An investigation was made into polystyrene (PS) grafted onto nanometre silicon carbide (SIC) particles. In our experiment, the grafting polymerization reaction was induced by a radio frequency (RF) inductively coupled plasma (ICP) treatment of the nanometre powder. FTIR (Fourier transform infrared spectrum) and XPS (X-ray photoelectron spectroscopy) results reveal that PS is grafted onto the surface of silicon carbide powder. An analysis is presented on the effectiveness of this approach as a function of plasma operating variables including the plasma treating power, treating time, and grafting reaction temperature and time.展开更多
In the determination of trace yttrium (Y) in an ytterbium (Yb) matrix byinductively coupled plasma atomic emission spectrometry (ICP-AES), the most prominent line ofyttrium, Y 371.030 nm line, suffers from strong inte...In the determination of trace yttrium (Y) in an ytterbium (Yb) matrix byinductively coupled plasma atomic emission spectrometry (ICP-AES), the most prominent line ofyttrium, Y 371.030 nm line, suffers from strong interference due to an emission line of ytterbium.In mis work, a method based on wavelet transform was proposed for the spectral interferencecorrection. Haar wavelet was selected as the mother wavelet. The discrete detail after the thirddecomposition, D3, was chosen for quantitative analysis based on the consideration of bothseparation degree and peak height. The linear correlation coefficient between the height of the leftpositive peak in D3 and the concentration of Y was calculated to be 0.9926. Six synthetic sampleswere analyzed, and the recovery for yttrium varied from 96.3 percent to 110.0 percent. The amountsof yttrium in three ytterbium metal samples were determined by the proposed approach with an averagerelative standard deviation (RSD) of 2.5 percent, and the detection limit for yttrium was 0.016percent. This novel correction technique is fast and convenient, since neither complicated modelassumption nor time-consuming iteration is required. Furthermore, it is not affected by thewavelength drift inherent in monochromators that will severely reduce the accuracy of resultsobtained by some chemometric methods.展开更多
The determination of trace impurities in high purity zinc oxide by high resolution inductively coupled plasma mass spectrometry ( HR-ICP-MS ) was investigated. To overcome some poteutially problematic spectral iuter...The determination of trace impurities in high purity zinc oxide by high resolution inductively coupled plasma mass spectrometry ( HR-ICP-MS ) was investigated. To overcome some poteutially problematic spectral iuterference, measurements were acquired in both middle and high resolution modes. The matrix effects due to the presence of excess HCl and zinc were evaluated. The optimum conditions for the determination were tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits ranged from 0.02μg/ g to 6 μg/ g depending on the elements. The experimental resalts for the determination of Na, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Mo, Cd, Sb and Pb in several high purity zinc oxide powders were presented.展开更多
A numerical model is developed to study the conductivity effects during the transition from collisionless to collisional regimes in cylindrical inductively coupled argon plasmas at pressures of 0.1-20 Pa.The model con...A numerical model is developed to study the conductivity effects during the transition from collisionless to collisional regimes in cylindrical inductively coupled argon plasmas at pressures of 0.1-20 Pa.The model consists of electron kinetics module,electromagnetics module,and global model module.It allows for self-consistent description of non-local electron kinetics and collisionless electron heating in terms of the conductivity of homogeneous hot plasma.Simulation results for non-local conductivity case are compared with predictions for the assumption of local conductivity case.Electron densities and effective electron temperatures under non-local and local conductivities show obvious differences at relatively low pressures.As increasing pressure,the results under the two cases of conductivities tend to converge,which indicates the transition from collisionless to collisional regimes.At relatively low pressures the local negative power absorption is predicted by non-local conductivity case but not captured by local conductivity case.The two-dimensional(2D)profiles of electron current density and electric field are coincident for local conductivity case in the pressure range of interest,but it roughly holds true for non-local conductivity case at very high pressure.In addition,an effective conductivity with consideration of non-collisional stochastic heating effect is introduced.The effective conductivity almost reproduces the electron density and effective electron temperature for the non-local conductivity case,but does not capture the non-local relation between electron current and electric field as well as the local negative power absorption that is observed for nonlocal conductivity case at low pressures.展开更多
In this study, a simple method for the simultaneous determination of trace metals(Cu, V, Co, Zn) in coastal seawater using the Mg(OH)2 coprecipitation inductively coupled plasma mass spectrometry(ICP-MS) was developed...In this study, a simple method for the simultaneous determination of trace metals(Cu, V, Co, Zn) in coastal seawater using the Mg(OH)2 coprecipitation inductively coupled plasma mass spectrometry(ICP-MS) was developed. This multi-element method enables the simultaneous extraction of four metals, particularly Co and V. The recoveries of Cu, Co, V and Zn after Mg(OH)2 coprecipitation were 73%, 96%, 94% and 92%, which means that our procedure was well-suited to the determination of these four trace metals. The detection limits were 3.81, 0.18, 6.09 and 1.91 nmol L-1, respectively. Then, applying this method to the simultaneous determination of these four metals in coastal water samples from the East China Sea revealed that the concentrations of Cu, Zn, Co and V were higher in bottom waters compared to water at other depths, and higher concentrations were generally observed at the Yangtze River estuary. Additionally, example vertical profiles of dissolved trace metal concentrations for the East China Sea in spring and autumn are compared. These findings indicate that Zn had the greatest seasonal variation followed by Cu, V and Co. For Zn and Co, the concentrations were higher during spring than during autumn. For Cu and V, the seasonal variation in the concentrations was opposite.展开更多
Changes of the electron dynamics in hydrogen (H2) radio-frequency (RF) inductively coupled plasmas are investigated using a hairpin probe and an intensified charged coupled device (ICCD). The electron density, p...Changes of the electron dynamics in hydrogen (H2) radio-frequency (RF) inductively coupled plasmas are investigated using a hairpin probe and an intensified charged coupled device (ICCD). The electron density, plasma emission intensity, and input current (voltage) are measured during the E to H mode transitions at different pressures. It is found that the electron density, plasma emission intensity, and input current jump up discontinuously, and the input voltage jumps down at the E to H mode transition points. And the threshold power of the E to H mode transition decreases with the increase of the pressure. Moreover, space and phase resolved optical emission spectroscopic measurements reveal that, in the E mode, the RF dynamics is characterized by one dominant excitation per RF cycle, while in the H mode, there are two excitation maxima within one cycle.展开更多
A two-dimensional self-consistent kinetic model was developed to study the influence of the various factors on the electron energy distribution function. These factors include gas pressure the driving frequency, the ...A two-dimensional self-consistent kinetic model was developed to study the influence of the various factors on the electron energy distribution function. These factors include gas pressure the driving frequency, the radius and length of the inductively coupled plasma equipment, the amplitude of the radio-frequency coil current, and the number of turns of rf coils. The spatial profiles of the rf electric field and power density have also been calculated under the same parameters. Numerical results show that the electron energy distribution functions are significantly modified and the spatial profiles of the rf electric field and rf power density are also demonstrated.展开更多
Trace elements were determined in high purity gold by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Sample were decomposed by aqua regia. To overcome some potentially problematic spectra/...Trace elements were determined in high purity gold by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Sample were decomposed by aqua regia. To overcome some potentially problematic spectra/ interference, measurements were acquired in both medium and high resolution modes. The matrix effects due to the presence of excessive HCl and Au were evaluated. The optimum conditions for the determination was tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits range from 0.01ug/g to 0.28ug/g depending on the elements. The method is accurate, quick and convenient. It has been applied to the determination of trace elements in high purity gold with satisfactory results.展开更多
By using temperature-dependent Hall, variable-frequency capacitance-voltage and cathodoluminescence (CL) measurements, the identification of inductively coupled plasma (ICP)-induced defect states around the AlxGa1...By using temperature-dependent Hall, variable-frequency capacitance-voltage and cathodoluminescence (CL) measurements, the identification of inductively coupled plasma (ICP)-induced defect states around the AlxGa1-xN/GaN heterointerface and their elimination by subsequent annealing in AlxGa1-xN/GaN heterostructures are systematically investigated. The energy levels of interface states with activation energies in a range from 0.211 to 0.253 eV below the conduction band of GaN are observed. The interface state density after the ICP-etching process is as high as 2.75× 10^12 cm^-2.eV^-1. The ICP-induced interface states could be reduced by two orders of magnitude by subsequent annealing in N2 ambient. The CL studies indicate that the ICP-induced defects should be Ga-vacancy related.展开更多
基金supported by the Scientific Research Foundation of Xijing University,China(No.XJ19T03)the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory(No.ZHD201701)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2024JC-YBMS-342).
文摘Enhancing plasma uniformity can be achieved by modifying coil and chamber structures in radio frequency inductively coupled plasma(ICP)to meet the demand for large-area and uniformly distributed plasma in industrial manufacturing.This study utilized a two-dimensional self-consistent fluid model to investigate how different coil configurations and chamber aspect ratios affect the radial uniformity of plasma in radio frequency ICP.The findings indicate that optimizing the radial spacing of the coil enhances plasma uniformity but with a reduction in electron density.Furthermore,optimizing the coil within the ICP reactor,using the interior point method in the Interior Point Optimizer significantly enhances plasma uniformity,elevating it from 56%to 96%within the range of the model sizes.Additionally,when the chamber aspect ratio k changes from 2.8 to 4.7,the plasma distribution changes from a center-high to a saddleshaped distribution.Moreover,the plasma uniformity becomes worse.Finally,adjusting process parameters,such as increasing source power and gas pressure,can enhance plasma uniformity.These findings contribute to optimizing the etching process by improving plasma radial uniformity.
基金financially supported by National Natural Science Foundation of China(NSFC)(Nos.12105035 and 11935005)Guangdong Basic and Applied Basic Research Foundation(No.2021B1515120018)+1 种基金the Fundamental Research Funds for the Central Universities(No.DUT21TD104)the Advanced Space Propulsion Laboratory of BICE and Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology(No.Lab ASP-2020-01)。
文摘To maintain the high-density plasma source in inductively coupled plasma(ICP),very high radiofrequency power is often delivered to the antenna,which can heat the dielectric windows near the antenna to high temperature.This high temperature can modulate the plasma characteristics to a large degree.We thus study the effect of dielectric window temperature on plasma parameters in two different ICP structures based on COMSOL software.The distributions of various plasma species are examined at different dielectric window temperatures.The concentration of neutral gas is found to be largely modulated at high dielectric window temperature,which further affects the electron collision probability with neutrals and the electron temperature.However,the electron density profiles are barely affected by the dielectric window temperature,which is mainly concentrated at the center of the reactor due to the fixed power input and pressure.
基金financially supported by National Natural Science Foundation of China(Nos.11935005 and 11875101)the Fundamental Research Funds for the Central Universities(No.DUT21LAB110)。
文摘In this work,a two-dimensional hybrid model,which consists of a bulk fluid module,a sheath module and an ion Monte-Carlo module,is developed to investigate the modulation of ion energy and angular distributions at different radial positions in a biased argon inductively coupled plasma.The results indicate that when the bias voltage amplitude increases or the bias frequency decreases,the ion energy peak separation width becomes wider.Besides,the widths of the ion energy peaks at the edge of the substrate are smaller than those at the center due to the lower plasma density there,indicating the nonuniformity of the ion energy distribution function(IEDF)along the radial direction.As the pressure increases from 1 to 10 Pa,the discrepancy of the IEDFs at different radial positions becomes more obvious,i.e.the IEDF at the radial edge is characterized by multiple low energy peaks.When a dual frequency bias source is applied,the IEDF exhibits three or four peaks,and it could be modulated efficiently by the relative phase between the two bias frequencies.The results obtained in this work could help to improve the radial uniformity of the IEDF and thus the etching process.
基金the Natural Science Foundation of Hunan Province, China (No. 05JJ40017).
文摘A An analytical method using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of 24 elements (Be, Mg, A1, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn Sb, Ba, Pt, Au, and Pb) in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCI. The matrix effects because of the presence of excess HCI and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination were tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits were 0.016-1.50 ].tg·g^-1, the recovery ratios were 92.2%-111.2%, and the RSD was less than 3.6%. The method was accurate, quick, and convenient. It was applied to the determination of trace impurities in high purity cobalt with satisfactory results.
文摘A study of Cl2/BCl3-based inductively coupled plasma (ICP) was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etching depths of more than 150μm. Plasma etch characteristics with ICP process pressure and the percentage of BCI3 were studied in greater detail at a constant ICP coil/bias power. The measured peak-to-peak voltage as a function of pressure was used to estimate the minimum energy of the ions bombarding the substrate. The process pressure was found to have a substantial influence on the energy of heavy ions. Various ion species in plasma showed minimum energy variation from 1.85 eV to 7.5 eV in the pressure range of 20 mTorr to 50 mTorr. The effect of pressure and the percentage of BCl3 on the etching rate and surface smoothness of the bottom surface of the etched hole were studied for a fixed total flow rate. The etching rate was found to decrease with the percentage of BCl3, whereas the addition of BCl3 resulted in anisotropic holes with a smooth veil free bottom surface at a pressure of 30 mTorr and 42% BC13. In addition, variation of the etching yield with pressure and etching depth were also investigated.
文摘ZrN fihns were deposited on Si(111) and M2 steel by inductively coupled plasma (ICP)-enhanced RF magnetron sputtering. The effect of ICP power on the microstructure, mechanical properties and corrosion resistance of ZrN films was investigated. When the ICP power is below 300 W, the ZrN films show a columnar structure. With the increase of ICP power, the texture coefficient (To) of the (111) plane, the nanohardness and elastic modulus of the films increase and reach the maximum at a power of 300 W. As the ICP Power exceeds 300 W, the films exhibit a ZrN and ZrNx mixed crystal structure without columnar grain while the nanohardness and elastic modulus of the films decrease. All the ZrN coated samples show a higher corrosion resistance than that of the bare M2 steel substrate in 3.5% NaCl electrolyte. The nanohardness and elastic modulus mostly depend on the crystalline structure and Tc of ZrN(111).
基金supported by Important National Science & Technology Specific Projects of China (No.2) (Nos.2009ZX02001,2011ZX02403)
文摘The geometry of an inductively coupled plasma (ICP) etcher is usually considered to be an important factor for determining both plasma and process uniformity over a large wafer. During the past few decades, these parameters were determined by the "trial and error" method, resulting in wastes of time and funds. In this paper, a new approach of regression orthogonal design with plasma simulation experiments is proposed to investigate the sensitivity of the structural parameters on the uniformity of plasma characteristics. The tool for simulating plasma is CFD-ACE+, which is commercial multi-physical modeling software that has been proven to be accurate for plasma simulation. The simulated experimental results are analyzed to get a regression equation on three structural parameters. Through this equation, engineers can compute the uniformity of the electron number density rapidly without modeling by CFD-ACE+. An optimization performed at the end produces good results.
基金The project supported by the Natural Science Foundation of Guangdong province (No. 000675) the Key project tackled of Guangdong province (ZKM01401G)
文摘The ion density distribution in the reaction chamber was diagnosed by a Langmuir probe. The rules of the ion density distribution were obtained under the pressures of 9 Pa, 13 Pa, 27 Pa and 53 Pa in the reaction chamber, different radio-frequency powers and different positions. The result indicates that the ion density decreases as the pressure increases, and increases as the power decreases. The ion density of axial position z =0 achieves 5.8×1010 on the center of coil under the power of 200 w and pressure of 9 Pa in the reaction chamber.
基金supported by the Natural Science Foundation of Hunan Province(No.05JJ40017)Education Department of Hunan Province(No.05B064).
文摘An analytical method using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of Be, Mg, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn, Sb, Ba, Pt, Au and Pb in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCl. The matrix effects due to the presence of excess HCl and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination was tested and discussed. Correction for matrix effects, Sc, Rh and Bi were used as internal standards. The detection limits is 0.003-0.57 μg/g, the recovery ratio is 92.2%-111.2%, and the RSD is less than 3.6%. The method is accurate, quick and convenient. It has been applied to the determination of trace impurities in high purity cobalt with satisfactory results.
基金The China Ocean Mineral Resources Research and Development Association Research Program of the State Oceanic Administration of China under contract No.DY125-13-R-07the National Natural Science Foundation of China under contract Nos 41322036 and 41230960+1 种基金the Shandong Provincial Natural Science Foundation of China under contract No.ZR2014DP009the Special Basic Research Funds for Central Public Research Institutes for The First Institute of Oceanography,State Oceanic Administration of China under contract Nos GY0213G06 and GY02-2012G35
文摘An improved analytical method to determine the content of 52 major, minor and trace elements in marine geological samples, using a HF-HCl-HNO_3 acid system with a high-pressure closed digestion method(HPCD), is studied by an inductively coupled plasma optical emission spectrometry(ICP-OES) and an inductively coupled plasma mass spectrometry(ICP-MS). The operating parameters of the instruments are optimized, and the optimal analytical parameters are determined. The influences of optical spectrum and mass spectrum interferences, digestion methods and acid systems on the analytical results are investigated. The optimal spectral lines and isotopes are chosen, and internal standard element of rhodium is selected to compensate for matrix effects and analytical signals drifting. Compared with the methods of an electric heating plate digestion and a microwave digestion, a high-pressure closed digestion method is optimized with less acid, complete digestion,less damage for digestion process. The marine geological samples are dissolved completely by a HF-HCl-HNO_3 system, the relative error(RE) for the analytical results are all less than 6.0%. The method detection limits are 2–40μg/g by the ICP-OES, and 6–80 ng/g by ICP-MS. The methods are used to determine the marine sediment reference materials(GBW07309, GBW07311, GBW07313), rock reference materials(GBW07103, GBW07104,GBW07105), and cobalt-rich crust reference materials(GBW07337, GBW07338, GBW07339), the obtained analytical results are in agreement with the certified values, and both of the relative standard deviation(RSD) and the relative error(RE) are less than 6.0%. The analytical method meets the requirements for determining 52 elements contents of bulk marine geological samples.
文摘An investigation was made into polystyrene (PS) grafted onto nanometre silicon carbide (SIC) particles. In our experiment, the grafting polymerization reaction was induced by a radio frequency (RF) inductively coupled plasma (ICP) treatment of the nanometre powder. FTIR (Fourier transform infrared spectrum) and XPS (X-ray photoelectron spectroscopy) results reveal that PS is grafted onto the surface of silicon carbide powder. An analysis is presented on the effectiveness of this approach as a function of plasma operating variables including the plasma treating power, treating time, and grafting reaction temperature and time.
文摘In the determination of trace yttrium (Y) in an ytterbium (Yb) matrix byinductively coupled plasma atomic emission spectrometry (ICP-AES), the most prominent line ofyttrium, Y 371.030 nm line, suffers from strong interference due to an emission line of ytterbium.In mis work, a method based on wavelet transform was proposed for the spectral interferencecorrection. Haar wavelet was selected as the mother wavelet. The discrete detail after the thirddecomposition, D3, was chosen for quantitative analysis based on the consideration of bothseparation degree and peak height. The linear correlation coefficient between the height of the leftpositive peak in D3 and the concentration of Y was calculated to be 0.9926. Six synthetic sampleswere analyzed, and the recovery for yttrium varied from 96.3 percent to 110.0 percent. The amountsof yttrium in three ytterbium metal samples were determined by the proposed approach with an averagerelative standard deviation (RSD) of 2.5 percent, and the detection limit for yttrium was 0.016percent. This novel correction technique is fast and convenient, since neither complicated modelassumption nor time-consuming iteration is required. Furthermore, it is not affected by thewavelength drift inherent in monochromators that will severely reduce the accuracy of resultsobtained by some chemometric methods.
文摘The determination of trace impurities in high purity zinc oxide by high resolution inductively coupled plasma mass spectrometry ( HR-ICP-MS ) was investigated. To overcome some poteutially problematic spectral iuterference, measurements were acquired in both middle and high resolution modes. The matrix effects due to the presence of excess HCl and zinc were evaluated. The optimum conditions for the determination were tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits ranged from 0.02μg/ g to 6 μg/ g depending on the elements. The experimental resalts for the determination of Na, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Mo, Cd, Sb and Pb in several high purity zinc oxide powders were presented.
基金sponsored by National Natural Science Foundation of China(Nos.12105041,11935005 and 12035003)Fundamental Research Funds for the Central Universities(No.2232020D-40)Shanghai Sailing Program(No.20YF1401300)。
文摘A numerical model is developed to study the conductivity effects during the transition from collisionless to collisional regimes in cylindrical inductively coupled argon plasmas at pressures of 0.1-20 Pa.The model consists of electron kinetics module,electromagnetics module,and global model module.It allows for self-consistent description of non-local electron kinetics and collisionless electron heating in terms of the conductivity of homogeneous hot plasma.Simulation results for non-local conductivity case are compared with predictions for the assumption of local conductivity case.Electron densities and effective electron temperatures under non-local and local conductivities show obvious differences at relatively low pressures.As increasing pressure,the results under the two cases of conductivities tend to converge,which indicates the transition from collisionless to collisional regimes.At relatively low pressures the local negative power absorption is predicted by non-local conductivity case but not captured by local conductivity case.The two-dimensional(2D)profiles of electron current density and electric field are coincident for local conductivity case in the pressure range of interest,but it roughly holds true for non-local conductivity case at very high pressure.In addition,an effective conductivity with consideration of non-collisional stochastic heating effect is introduced.The effective conductivity almost reproduces the electron density and effective electron temperature for the non-local conductivity case,but does not capture the non-local relation between electron current and electric field as well as the local negative power absorption that is observed for nonlocal conductivity case at low pressures.
基金financially supported by the National Natural Science Foundation of China (Nos. 41140037, 41276069)the Young Scientist Award Science Foundation of Shandong, China (BS2010HZ026)the Open Science Funding of the Key Laboratory of the First Institute of Oceanography, SOA (MESE-2011-03)
文摘In this study, a simple method for the simultaneous determination of trace metals(Cu, V, Co, Zn) in coastal seawater using the Mg(OH)2 coprecipitation inductively coupled plasma mass spectrometry(ICP-MS) was developed. This multi-element method enables the simultaneous extraction of four metals, particularly Co and V. The recoveries of Cu, Co, V and Zn after Mg(OH)2 coprecipitation were 73%, 96%, 94% and 92%, which means that our procedure was well-suited to the determination of these four trace metals. The detection limits were 3.81, 0.18, 6.09 and 1.91 nmol L-1, respectively. Then, applying this method to the simultaneous determination of these four metals in coastal water samples from the East China Sea revealed that the concentrations of Cu, Zn, Co and V were higher in bottom waters compared to water at other depths, and higher concentrations were generally observed at the Yangtze River estuary. Additionally, example vertical profiles of dissolved trace metal concentrations for the East China Sea in spring and autumn are compared. These findings indicate that Zn had the greatest seasonal variation followed by Cu, V and Co. For Zn and Co, the concentrations were higher during spring than during autumn. For Cu and V, the seasonal variation in the concentrations was opposite.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11075029,11175034,and 11205025)the Fundamental Research Funds for Central Universities,China(Grant No.DUT12RC(3)14)
文摘Changes of the electron dynamics in hydrogen (H2) radio-frequency (RF) inductively coupled plasmas are investigated using a hairpin probe and an intensified charged coupled device (ICCD). The electron density, plasma emission intensity, and input current (voltage) are measured during the E to H mode transitions at different pressures. It is found that the electron density, plasma emission intensity, and input current jump up discontinuously, and the input voltage jumps down at the E to H mode transition points. And the threshold power of the E to H mode transition decreases with the increase of the pressure. Moreover, space and phase resolved optical emission spectroscopic measurements reveal that, in the E mode, the RF dynamics is characterized by one dominant excitation per RF cycle, while in the H mode, there are two excitation maxima within one cycle.
基金the National Science Foundation of China(Nos.10376003,10572035)
文摘A two-dimensional self-consistent kinetic model was developed to study the influence of the various factors on the electron energy distribution function. These factors include gas pressure the driving frequency, the radius and length of the inductively coupled plasma equipment, the amplitude of the radio-frequency coil current, and the number of turns of rf coils. The spatial profiles of the rf electric field and power density have also been calculated under the same parameters. Numerical results show that the electron energy distribution functions are significantly modified and the spatial profiles of the rf electric field and rf power density are also demonstrated.
基金Funded by the Hunan Provincial Natural Science Foundation of China(No.05JJ40017)Hunan Provincial Education Department of China (No.07C029 , 08C260)
文摘Trace elements were determined in high purity gold by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Sample were decomposed by aqua regia. To overcome some potentially problematic spectra/ interference, measurements were acquired in both medium and high resolution modes. The matrix effects due to the presence of excessive HCl and Au were evaluated. The optimum conditions for the determination was tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits range from 0.01ug/g to 0.28ug/g depending on the elements. The method is accurate, quick and convenient. It has been applied to the determination of trace elements in high purity gold with satisfactory results.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.60906041,10774001,60736033,and 60890193)the National Basic Research Program of China (Grant Nos.2006CB604908 and 2006CB921607)
文摘By using temperature-dependent Hall, variable-frequency capacitance-voltage and cathodoluminescence (CL) measurements, the identification of inductively coupled plasma (ICP)-induced defect states around the AlxGa1-xN/GaN heterointerface and their elimination by subsequent annealing in AlxGa1-xN/GaN heterostructures are systematically investigated. The energy levels of interface states with activation energies in a range from 0.211 to 0.253 eV below the conduction band of GaN are observed. The interface state density after the ICP-etching process is as high as 2.75× 10^12 cm^-2.eV^-1. The ICP-induced interface states could be reduced by two orders of magnitude by subsequent annealing in N2 ambient. The CL studies indicate that the ICP-induced defects should be Ga-vacancy related.