scholarly journals Plasma Parameters and Etching Characteristics of SiOxNy Films in CF4 + O2 + X (X = C4F8 or CF2Br2) Gas Mixtures

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5476
Author(s):  
Yunho Nam ◽  
Alexander Efremov ◽  
Byung Jun Lee ◽  
Kwang-Ho Kwon
Keyword(s):  
Photoelectron Spectroscopy ◽  
Process Condition ◽  
Input Power ◽  
Active Species ◽  
Diagnostic Tools ◽  
Plasma Parameters ◽  
Additive Component ◽  
Etching Profile ◽  
Polymer Deposition ◽  
Ion Current Density

In this work, we carried out the study of CF4 + O2 + X (X = C4F8 or CF2Br2) gas chemistries in respect to the SiOxNy reactive-ion etching process in a low power regime. The interest in the liquid CF2Br2 as an additive component is motivated by its generally unknown plasma etching performance. The combination of various diagnostic tools (double Langmuir probe, quadrupole mass-spectrometry, X-ray photoelectron spectroscopy) allowed us to compare the effects of CF4/X mixing ratio, input power and gas pressure on gas-phase plasma characteristics as well as to analyze the SiOxNy etching kinetics in terms of process-condition-dependent effective reaction probability. It was found that the given gas systems are characterized by: (1) similar changes in plasma parameters (electron temperature, ion current density) and fluxes of active species with variations in processing conditions; (2) identical behaviors of SiOxNy etching rates, as determined by the neutral-flux-limited process regime; and (3) non-constant SiOxNy + F reaction probabilities due to changes in the polymer deposition/removal balance. The features of CF4 + CF2Br2 + O2 plasma are lower polymerization ability (due to the lower flux of CFx radicals) and a bit more vertical etching profile (due to the lower neutral/charged ratio).

scholarly journals PLASMA PARAMETERS AND ACTIVE SPECIES KINETICS IN CF4+C4F8+Ar GAS MIXTURE

2018 ◽  
Vol 61 (4-5) ◽  
pp. 31
Author(s):  
Alexander M. Efremov ◽  
Dmitriy B. Murin ◽  
Kwang H. Kwon
Keyword(s):  
Inductively Coupled Plasma ◽  
Ion Bombardment ◽  
Volume Density ◽  
Input Power ◽  
Active Species ◽  
Gas Mixture ◽  
Mixing Ratio ◽  
Plasma Parameters ◽  
Bias Power ◽  
Ar Gas

This work discusses the relationships between the initial composition of the CF4 + C4F8 + Ar gas mixture, gas-phase characteristics and heterogeneous process kinetics under the condition of low-pressure inductively coupled plasma. The goals were to investigate how the CF4/C4F8 mixing ratio influences internal plasma parameters (electron temperature, electron density and ion bombardment energy) and kinetics of plasma active species as well as to analyze how the changes in above parameters may influence the dry etching characteristics, such as etching rates and selectivities. The investigation was carried out using the combination of plasma diagnostics by double Langmuir probes and 0-dimensional plasma modeling. Both experiments and calculations were carried out at constant gas pressure (10 mTorr), input power (800 W) and bias power (150 W) while the CF4/C4F8 mixing ratio was varied through the partial flow rates for corresponding gases. It was shown that the substitution of CF4 for C4F8 in the CF4+C4F8+Ar feed gas lowers F atom formation rates and causes the decreasing F atom flux to the treated surface due to decreasing their volume density. It was proposed that an increase in the densities and fluxes of unsaturated CFx (x=1,2) radicals toward C4F8-rich plasmas at the nearly constant ion energy flux (i.e. at the nearly constant efficiency of ion bombardment) causes a decrease in the effective reaction probability for F atoms through the increasing thickness of the fluorocarbon polymer film on the treated surface.Forcitation:Efremov A.M., Murin D.B., Kwon K.H. Plasma parameters and active species kinetics CF4+C4F8+Ar gas mixture. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N4-5. P. 31-36

scholarly journals PLASMA PARAMETERS AND KINETICS OF ACTIVE SPECIES IN HBr + Cl2 + O2 GAS MIXTURE

2019 ◽  
Vol 62 (7) ◽  
pp. 72-79
Author(s):  
Aleksandr M. Efremov ◽  
Vladimir B. Betelin ◽  
Kwang-Ho Kwon ◽  
Dmitriy G. Snegirev
Keyword(s):  
Variable Parameter ◽  
Plasma Chemistry ◽  
Input Power ◽  
Active Species ◽  
Gas Mixture ◽  
Mixing Ratio ◽  
Plasma Parameters ◽  
Experimental Conditions ◽  
Bias Power ◽  
Atom Density

In this work, we performed the combined (experimental and model-based) study of gas-phase plasma characteristics for HBr + Cl2 + O2 gas mixture under conditions of low-pressure inductive 13.56 MHz discharge. The data on internal plasma parameters, plasma chemistry as well as the steady-state plasma composition were obtained using a combination of Langmuir probe diagnostics and 0-dimensional (global) plasma modeling. Both experimental and modeling procedures were carried out at constant total gas pressure (p = 10 mTorr), input power (W = 500 W), bias power (Wdc = 200 W) and O2 fraction in a feed gas (y(O2) = 11 %). The variable parameter was the HBr + Cl2 mixing ratio, which was changed in the range of 0 – 89 % Cl2. It was found that, under the given set of experimental conditions, the substitution of HBr for Cl2: 1) results in increasing both mean electron energy and electron density; 2) causes the mon-monotonic (with a maximum at ~ 45 % Cl2) change in Br atom density; and 3) provides an increase in O atom density at y(O2) = const. The possible impacts of HBr + Cl2 mixing ratio on Si and SiO2 etching kinetics were estimated through the analysis of model-predicted fluxes for plasma active species (Br, Cl and O atoms, positive ions).

scholarly journals PLASMA PARAMETERS AND COMPOSITION IN CF4 + O2 + Ar AND CHF3 + O2 +Ar IN REACTIVE ION ETCHING PROCESSES

2019 ◽  
Vol 62 (12) ◽  
pp. 108-118
Author(s):  
Alexander M. Efremov ◽  
Alexander M. Sobolev ◽  
Vladimir B. Betelin ◽  
Kwang-Ho Kwon
Keyword(s):  
Steady State ◽  
Reactive Ion Etching ◽  
Plasma Chemistry ◽  
Input Power ◽  
Active Species ◽  
Plasma Parameters ◽  
Ion Etching ◽  
Bias Power ◽  
State Densities ◽  
Silicon Based

The comparative analysis of both CF4+O2+Ar and CHF3+O2+Ar plasma systems under the typical conditions of reactive ion etching of silicon and silicon-based compounds was carried out. The data on internal plasma parameters, plasma chemistry as well as the steady-state plasma composition were obtained using a description of Langmuir probe diagnostics and 0-dimensional (global) plasma modeling. As a presented in the literature, both experimental and modeling procedures were carried out at constant total gas pressure, input power, bias power. The obtained results allowed one 1) to figure out the influence of oxygen on steady-state densities of plasma active species through the kinetics of both electron-impact and atom-molecular reactions; 2) to understand the features of fluorine atoms and fluorocarbon radicals kinetics which determine chemical activity and  polymerization ability of  plasmas in respect to treated surfaces; 3) to perform the model-bases analysis of  heterogeneous process kinetics (etching, polymerization, polymer destruction) which determine the overall etching regime and output parameters. It was found that the substitution of argon for oxygen in both gas mixtures 1) results in monotonic increase in fluorine atom density; 2) is accompanied by decreasing polymerization ability of a gas phase and 3) causes the rapid (by about two orders of magnitude at ~ 20% О2) decrease in fluorocarbon polymer film thickness with the higher values for CHF3+O2+Ar system.

scholarly journals PLASMA PARAMETERS, DENSITIES OF ACTIVE SPECIES AND ETCHING KINETICS IN C4F8+Ar GAS MIXTURE

2019 ◽  
Vol 62 (2) ◽  
pp. 31-37
Author(s):  
Alexander M. Efremov ◽  
Dmitry B. Murin ◽  
Kwang H. Kwon
Keyword(s):  
Steady State ◽  
Plasma Chemistry ◽  
Input Power ◽  
Active Species ◽  
Gas Mixture ◽  
Plasma Parameters ◽  
Experimental Conditions ◽  
Bias Power ◽  
Positive Ions ◽  
Ar Gas

In this work, we performed the combined (experimental and model-based) study of gas-phase plasma characteristics and etching kinetics for both Si and SiO2 in the C4F8 + Ar gas mixture. The experiments were carried out at constant total gas pressure (p = 6 mTorr), input power (W = 900 W) and bias power (Wdc = 200 W) while the C4F8/Ar mixing ratio was varied in the range of 0–75% Ar. The data on internal plasma parameters, plasma chemistry as well as the steady-state plasma composition were obtained by both Langmuir probe diagnostics and 0-dimensional plasma modeling. The etching mechanisms were investigated through the analysis of relationships between the measured etching rates and the model-predicted fluxes of active species (F atoms, polymerizing CFx radicals and positive ions). It was found that, under the given set of experimental conditions, the Si and SiO2 etching process 1) appears in the steady-state etching regime; 2) exhibits the features of the ion-assisted chemical reactions in the neutral-flux-limited mode; and 3) is influenced by the fluorocarbon polymer film thickness. It was shown that the influence of input process parameters on the effective probability of chemical reaction between Si, SiO2 and fluorine atoms may be adequately characterized by the fluorocarbon radicals/fluorine atoms and fluorocarbon radicals/ion energy flux ratios.

PLASMA PARAMETERS, DENSITIES OF ACTIVE SPECIES AND ETCHING KINETICS IN C4F8+Ar GAS MIXTURE

1970 ◽  
Author(s):  
Alexander M. Efremov ◽  
Dmitry B. Murin ◽  
Kwang H. Kwon
Keyword(s):  
Steady State ◽  
Plasma Chemistry ◽  
Input Power ◽  
Active Species ◽  
Gas Mixture ◽  
Plasma Parameters ◽  
Experimental Conditions ◽  
Bias Power ◽  
Positive Ions ◽  
Ar Gas

In this work, we performed the combined (experimental and model-based) study of gas-phase plasma characteristics and etching kinetics for both Si and SiO2 in the C4F8 + Ar gas mixture. The experiments were carried out at constant total gas pressure (p = 6 mTorr), input power (W = 900 W) and bias power (Wdc = 200 W) while the C4F8/Ar mixing ratio was varied in the range of 0–75% Ar. The data on internal plasma parameters, plasma chemistry as well as the steady-state plasma composition were obtained by both Langmuir probe diagnostics and 0-dimensional plasma modeling. The etching mechanisms were investigated through the analysis of relationships between the measured etching rates and the model-predicted fluxes of active species (F atoms, polymerizing CFx radicals and positive ions). It was found that, under the given set of experimental conditions, the Si and SiO2 etching process 1) appears in the steady-state etching regime; 2) exhibits the features of the ion-assisted chemical reactions in the neutral-flux-limited mode; and 3) is influenced by the fluorocarbon polymer film thickness. It was shown that the influence of input process parameters on the effective probability of chemical reaction between Si, SiO2 and fluorine atoms may be adequately characterized by the fluorocarbon radicals/fluorine atoms and fluorocarbon radicals/ion energy flux ratios.

scholarly journals Dry Etching Performance and Gas-Phase Parameters of C6F12O + Ar Plasma in Comparison with CF4 + Ar

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1595
Author(s):  
Nomin Lim ◽  
Yeon Sik Choi ◽  
Alexander Efremov ◽  
Kwang-Ho Kwon
Keyword(s):  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Reactive Ion Etching ◽  
Research Work ◽  
Optical Emission ◽  
Plasma Parameters ◽  
Ion Etching ◽  
Ar Plasma ◽  
Ar Gas ◽  
Etching Selectivity

This research work deals with the comparative study of C6F12O + Ar and CF4 + Ar gas chemistries in respect to Si and SiO2 reactive-ion etching processes in a low power regime. Despite uncertain applicability of C6F12O as the fluorine-containing etchant gas, it is interesting because of the liquid (at room temperature) nature and weaker environmental impact (lower global warming potential). The combination of several experimental techniques (double Langmuir probe, optical emission spectroscopy, X-ray photoelectron spectroscopy) allowed one (a) to compare performances of given gas systems in respect to the reactive-ion etching of Si and SiO2; and (b) to associate the features of corresponding etching kinetics with those for gas-phase plasma parameters. It was found that both gas systems exhibit (a) similar changes in ion energy flux and F atom flux with variations on input RF power and gas pressure; (b) quite close polymerization abilities; and (c) identical behaviors of Si and SiO2 etching rates, as determined by the neutral-flux-limited regime of ion-assisted chemical reaction. Principal features of C6F12O + Ar plasma are only lower absolute etching rates (mainly due to the lower density and flux of F atoms) as well as some limitations in SiO2/Si etching selectivity.

Structure and Electrical Properties of Pulsed Laser Deposited Amorphous Carbon Nitride Thin Films

2002 ◽  
Vol 750 ◽  
Author(s):  
Yoshifumi Aoi ◽  
Kojiro Ono ◽  
Kunio Sakurada ◽  
Eiji Kamijo
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Photoelectron Spectroscopy ◽  
Pulsed Laser ◽  
Film Surface ◽  
Input Power ◽  
Localized States ◽  
Active Nitrogen ◽  
Deposited Films

ABSTRACTAmorphous CNx thin films were deposited by pulsed laser deposition (PLD) combined with a nitrogen rf radical beam source which supplies active nitrogen species to the growing film surface. The deposited films were characterized by X-ray photoelectron spectroscopy (XPS), Raman scattering, and Fourier transform infrared (FTIR) spectroscopy. Nitrogen content of the deposited films increased with increasing rf input power and N2 pressure in the PLD chamber. The maximum N/C ratio 0.23 was obtained at 400 W of rf input power and 1.3 Pa. XPS N 1s spectra shows the existence of several bonding structures in the deposited films. Electrical properties of the deposited films were investigated. The electrical conductivity decreased with increasing N/C atomic ratio. Temperature dependence of electrical conductivity measurements indicated that electronic conduction occurred by variable-range hopping between p electron localized states.

scholarly journals Preparation and Photocatalytic Performances of WO3/TiO2 Composite Nanofibers

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xiuping Han ◽  
Binghua Yao ◽  
Keying Li ◽  
Wenjing Zhu ◽  
Xuyuan Zhang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Photocatalytic Oxidation ◽  
Composite Nanofibers ◽  
Photogenerated Electron ◽  
Xrd Analysis ◽  
Catalytic Performance ◽  
Active Species ◽  
X Ray ◽  
Bet Analysis ◽  
Electron Holes

The use of sunlight for photocatalytic oxidation is an ideal strategy, but it is limited by factors such as insufficient light absorption intensity of the photocatalyst and easy recombination of photogenerated electron holes. TiO2 is favored by researchers as an environment-friendly catalyst. In this paper, TiO2 is combined with WO3 to obtain a nanofiber with excellent catalytic performance under sunlight. The WO3/TiO2 composite nanofibers were synthesized by using the electrospinning method. The X-ray diffraction (XRD) analysis indicated that WO3 was successfully integrated onto the surface of TiO2. The photodegradation performance and photocurrent analysis of the prepared nanofibers showed that the addition of WO3 really improved the photocatalytic performance of TiO2 nanofibers, methylene blue (MB) degradation rate increased from 72% to 96%, and 5% was the optimal composite mole percentage of W to Ti. The scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectra (UV-Vis DRS), and Brunauer-Emmett-Teller (BET) analysis further characterized the properties of 5% WO3/TiO2 nanofibers. The H2 generation rate of 5% WO3/TiO2 nanofibers was 107.15 μmol·g−1·h−1, in comparison with that of TiO2 nanofibers (73.21 μmol·g−1·h−1) under the same condition. The 5% WO3/TiO2 produced ·OH under illumination, which played an important role in the MB degradation. Also, the enhanced photocatalytic mechanism was also proposed based on the detailed analysis of the band gap and the active species trapping experiment. The results indicated that the effective separation of Z-scheme photogenerated electron-hole pairs and transfer system constructed between TiO2 and WO3 endowed the excellent photocatalytic activity of 5% WO3/TiO2 nanofibers.

Silver Thin Films Deposited by Compact Magnetron Sputtering System

2010 ◽  
Vol 93-94 ◽  
pp. 413-416 ◽  
Author(s):  
N. Promros ◽  
Boonchoat Paosawatyanyong
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Input Power ◽  
Grain Structure ◽  
Plasma Parameters ◽  
Glass Substrates ◽  
Sputtering Power ◽  
Silver Thin Films ◽  
Alloy Magnet ◽  
Sputtering System

A compact dc magnetron sputtering system capable of silver thin films depositions was designed and constructed. The novel small footprint sputtering head with target diameter of 52 mm was constructed utilizing powerful neodymium alloy magnet. Silver metal was sputter-deposited under various powers. Plasma parameters were analyzed by using the sweeping-bias single langmuir probe. The electron temperatures of the plasma glow were constant at approximately 2 eV even with the increasing of input power whereas plasma density increases with the increasing of the input power. The X-ray diffraction analysis (XRD) and scanning electron microscope (SEM) were used to study the crystalline structure and the surface morphology of the obtained silver thin films. Crystalline orientations of (111) and (200) in the silver films deposited on slide glass substrates were revealed from XRD pattern. The highest degrees of (111) and (200) orientations was obtained at the sputtering power between 0.228 and 0.265 Wcm-2. Sub-micron crystalline silver grain structure were observed using SEM micrographs. Facetted grain size and deposition rate of silver thin films increases as the sputtering power increases.

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