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This chapter (The Inductively Coupled Plasma) is a contribution to the Geostandards and Geoanalytical Research Handbook of Rock and Mineral Analysis – an online textbook that is a fully revised and updated edition of A Handbook of Silicate Rock Analysis (P. J. Potts, 1987, Blackie, Glasgow). Chapter 5 (from Section 1 of the handbook dealing with fundamentals of measurement and instrument design) is a comprehensive treatment of the inductively coupled plasma – a significant cornerstone of modern geoanalytical spectrometry. The Chapter includes discussion of plasma formation and key components of the ICP source. This is followed by an examination of the challenges of sample introduction into the plasma, particularly focussed on the introduction of liquid samples. The physical structure of the plasma, its robustness and interference effects are fully examined prior to a section dealing with how the operation of plasma is optimised in practise. [ABSTRACT FROM AUTHOR]

A generalized inductively coupled plasma (ICP) efficiency model is derived, which may be used to predict plasma generation efficiency with many types of radio frequency (RF) electric propulsion system. The analytical ICP discharge model is used to examine device scaling, and investigate trends in ICP performance as a function of geometry and system inputs. The ICP efficiency model is applied to an analytical RF cathode model to predict device behavior. Results from the updated RF cathode model show improvements in agreement with experimental data. [ABSTRACT FROM AUTHOR]

All human beings need healthy nutrition to grow, so the lack or excess of low-amount elements causes diseases in humans, for this reason, it is essential to know the presence of elements in food. Arak aluminum production factory is located next to Chogha village, so it is necessary to study the effects of this factory and other industries in the region on its agricultural products. In this study, the content of 11 elements was determined: aluminum, bromine, calcium, chlorine, iron, magnesium, manganese, potassium, sodium, scandium, and zinc in crops as wheat, barley, peas, beans and alfalfa prepared from the village of Chogha in the Arak region by neutron activation analysis, as well as 3 other elements, including arsenic, lead, and cadmium were determined by inductively coupled plasma analysis. Magnesium concentration from 1310 to 3970, manganese from 15.2 to 66.3, sodium from 14.2 to 1490, aluminum from 5.72 to 914, chlorine from 364 to 12000, calcium from 413 to 29600, bromine from 0.23 to 14.50, potassium from 4740 to 14700, iron from 10.1 to 1310.0, scandium from 0.033 to 4.02, zinc from 27.7 to 96.7, arsenic from 0.000 to 0.021, lead from 0.000 to 0.003 and cadmium from 0.00 to 0.02 mg/kg. The results show that the concentration of chlorine, manganese, magnesium, iron, sodium, aluminum, bromine, calcium, scandium, zinc, and lead in alfalfa, the concentration of potassium in pinto beans, the concentration of cadmium in barley, and the concentration of arsenic in wheat are higher than another analyzed sample.

This article investigates the plasma‐enhanced chemical vapor deposition of a‐C:H:SiOx coatings in a non‐self‐sustaining arc discharge plasma with a hot cathode in combination with a low‐frequency (200 kHz) inductively coupled plasma. It is shown that increasing the inductor power from 0 to 600 W leads to a twofold increase in the ion current density on the substrate. An increase in ion bombardment intensity results in a 1.3‐fold reduction in the coating's growth rate due to the resputtering phenomenon, a 1.5‐fold reduction in surface roughness, and an improvement in the mechanical properties of the coatings. The hardness of the coating is increased by 9–11%, the plasticity index by 10–17%, and the resistance to plastic deformation by 32–49%. [ABSTRACT FROM AUTHOR]

This paper presents the physical characteristics of 2D and 3D simulation of inductively coupled plasma (ICP) discharge with varying designs of copper coil. The inductive coil gaps are arranged at different distances and their physical properties are investigated in an argon environment. The optimal coil gap distance is determined to yield the highest electron density, electron temperature, and macroscopic gas temperature. Subsequently, the inductive coils on the quartz tube are repositioned without altering the gap between the coils, and the dielectric thickness is changed for optimized design then discharge properties are examined in an argon atmosphere. The maximum electron density, and macroscopic gas temperature are then obtained in the most advantageous position and dielectric thicknesses for the discharge process. [ABSTRACT FROM AUTHOR]

This research examines the impact of the coefficient of secondary electron emission (SEE) on various discharge features of plasma to improve the performance of deposited thin films. Unlike previous studies, we employed two-dimensional numerical modeling (2D) of an ICP reactor at a radiofrequency of 13.56 MHz and a low pressure of 1 Torr, using a finite element approach. This detailed investigation into parameters such as ionization rate, electric field, electron temperature, and electron density provides new insights into plasma interactions. Our findings reveal a significant correlation between the SEE coefficient and key plasma attributes. Notably, increased secondary electrons lead to a substantial rise in electron density and a reduction in sheath thickness, indicating an impactful change in the spatial distribution of plasma particles. Additionally, electron temperature increases exclusively in sheath regions, a novel observation not reported in earlier studies. Furthermore, higher SEE coefficients correlate with increased ionization rates within each sheath, suggesting a crucial role in maintaining discharge processes. This comprehensive analysis uncovers complex interdependencies within the plasma discharge system, offering valuable advancements for thin film deposition techniques.

Ultrafine semiconductor fabrication by lithography has undergone a significant transition from deep ultraviolet (DUV) to extreme ultraviolet (EUV) processes, which presents new challenges. Specifically, the damage caused to components utilized in an EUV system, such as multilayer mirrors, reticles, and pellicles within lithography equipment, owing to EUV-induced H2 plasma, is a critical issue that directly affects the process yield and equipment lifespan. To address these issues, it is crucial to establish an environment similar to that of EUV-induced plasma and develop a method to evaluate the resulting damage. Accordingly, an evaluation method is developed for assessing the material damage caused by hydrogen radicals and ions in inductively coupled H2 plasma. In these systems, the electron density ranged from 5 × 108 to 3.5 × 1010 cm−3, the electron temperature ranged from 1 to 4 eV, and the ion energy ranged from several to tens of eV; these conditions closely align with the environment of an EUV-induced H2 plasma. The damage to Mo2C, a potential EUV pellicle material, is quantitatively analyzed by measuring the fraction of the pore area and examining the chemical characteristics after exposing the samples to various plasma conditions, including electron density, gas pressure, and exposure time. [ABSTRACT FROM AUTHOR]

We compared the production rates and the destruction frequencies of ammonia in inductively coupled H2O/N2 and H2/N2 plasmas. We observed that the production rates of ammonia ranged between 4 and 7 μmol/s both in the H2O/N2 and H2/N2 plasmas generated at rf powers between 100 and 160 W, corresponding to the energy cost of 23–25 mol/MJ. Almost the same production rates suggest the usefulness of H2O as the resource for hydrogenation of atomic nitrogen adsorbed on surfaces. On the other hand, the destruction frequency was 2–4 times higher in the H2O/N2 than H2/N2 plasmas. Although the H2O/N2 plasma has a drawback in the destruction frequency, the present work shows its potential for the direct synthesis of ammonia from water with skipping the production of hydrogen. [ABSTRACT FROM AUTHOR]

The dependence of the parameters of low-pressure inductively coupled argon plasma (13.3–113 Pa) and field frequency of 13.56 MHz at the coil on the potential applied to the electrode and on gas flow rate up to 4000 sccm is numerically studied. The model is developed in the COMSOL Multiphysics environment and verified with experimental data, as well as over the Knudsen number. As a result of a numerical experiment, it is revealed as follows: when the displacement potential increases linearly, the density of charged particles increases exponentially and a slight increase in the electron temperature is observed; when the gas flow rate increases linearly, the density of charged particles increases exponentially, the density of excited states has an extremum at 2000 sccm, and the gas and electron temperature increases linearly. [ABSTRACT FROM AUTHOR]

The vacuum ultraviolet (VUV) light source derived from the Kr-He discharge is widely used for organic analysis, however the relevant model that greatly facilitates the design of high-performance VUV light sources remains to be developed. This study explores a model for simulating the light intensity of the VUV lamps based on the inductively coupled plasma (ICP) discharge in the low-pressure Kr-He mixture. Two typical ICP based light sources, i.e., a 13.56 MHz VUV lamp with an external coil and a 2.65 MHz VUV lamp with an internal coil, were successfully simulated with the COMSOL Multiphysics software coupled with a fluid model. The rate coefficients of the main reactions involved in the production of VUV radiations from Kr-He plasma were summarized and input in the model. The concentrations of Kr*(3P1) and Kr*(1P1), which are main VUV-generation species, were set as output to evaluate the overall light intensity of the VUV lamp. As a result, the optimal designing parameters (the length and density of the coil and the radius of the lamp) as well as operating parameters (the input power, the pressure inside the lamp, and the mixing ratio of Kr to He) were obtained for the maximum light intensity. The reliability of the model was further verified by comparing the measured photon flux with the simulated concentrations of Kr*(3P1) and Kr*(1P1) as functions of the pressure and mixing ratio of Kr-He mixture, which showed good agreements in variation tends. The model provides a great convenience for the development of ICP based VUV lamp with high light intensity and stability. [ABSTRACT FROM AUTHOR]

Plasma-assisted aerosol deposition (PAD) is a new ceramic coating technology that utilizes a low-pressure induction plasma jet to accelerate particles toward the substrate and form a coating. This plasma jet was generated by a radio frequency (RF) inductively coupled plasma torch under reduced pressure. Although the particle velocity was expected to directly influence the phenomena of particle collision, adhesion, and coating formation, it has not been investigated systematically. Thus, we aimed to clarify the velocity of particles accelerated by a subsonic or supersonic low-pressure induction plasma jet using a convergent-divergent (C-D) nozzle. The particles' velocity colliding with the substrate was measured using a time-of-flight method. The effects of the C-D nozzle, input RF power, and carrier gas flow rate on the particle velocity were investigated for alumina and yttria-stabilized zirconia particles. The use of the C-D nozzle increased the particle velocity, significantly, while the input RF power was an insensitive parameter for the particle velocity. This study implies the introduction of the C-D nozzle is effective on the particle acceleration in PAD. [ABSTRACT FROM AUTHOR]

This article analyzes the approaches to macro- and mesoscale computational modeling of the dynamics of metal powder particles motion in the condensation chamber of a plasma reactor, spheroidization, coagulation, and phase transitions in particles. The features of different regimes of vaporization and condensation were described. The influence of phenomena such as Brownian motion and thermophoresis on the process was explored. The parameters of the process at which the formation of core-shell particles occurs were determined. The model can be used to optimize and select the effective regimes for the processing and synthesis of powder materials in inductively coupled plasma.

The effect of plasma activation of reactive gas on the process of reactive magnetron synthesis of oxide coatings was theoretically and experimentally investigated using a radio-frequency inductively coupled plasma source, which creates a flow of activated reactive gas directed towards the surface on which the oxide coating is deposited. The reactive gas passes through a dense inductively coupled plasma located inside the plasma source, while argon is supplied through a separate channel near the magnetron. A theoretical model has been built allowing the calculation of spatial distributions of fluxes of metal atoms and molecules of activated reaction gas, as well as the stoichiometry area of the synthesized coatings. Calculations were performed on the example of aluminum oxide. It was found that the plasma activation of the reactive gas allows to increase the sticking coefficient of oxygen to the surface of the growing coating from values less than 0.1 for non-activated molecular oxygen to 0.9 when 500 W of RF power is introduced into the inductive discharge. In order to verify the developed model, experiments were conducted on depositing an aluminum oxide film on glass substrates located at different distances from the magnetron target, followed by measuring the distribution of film transparency along the substrate length and comparing it with the calculated distribution. A comparison of the calculation results with the experimental data shows a good agreement in the entire studied range of parameters. Based on the generalization of the obtained results, an empirical rule was formulated that the power ratio of the magnetron discharge and the plasma activator should be approximately 8:1.

A developed technological reactor for the formation of a diamond-like carbon coating on substrates up to 200 mm in diameter by chemical vapor deposition in high-density inductively coupled plasma at an operating pressure below 5 Pa is described. The results of experimental studies on obtaining a diamond-like carbon coating in the developed reactor are presented. The dependences of the rate of deposition of a diamond-like carbon coating on the power of the RF discharge, the operating pressure, and the consumption of the film-forming gaseous reagent have been established. Also, for the developed technological reactor, the modes for obtaining diamond-like carbon coatings with the best mechanical properties were established with the following process parameters: RF power 600–900 W, precursor gas flow rate 15–50 cm3/min, the ratio of plasma-forming gas volumes to film-forming gas volume 3:1 at a residual pressure in the working chamber of not more than 4 Pa. It has been shown by Raman spectroscopy that the coatings obtained under efficient conditions contain a significant amount of a diamond-like phase.

A mathematical model of a technical RF inductively coupled plasma is presented. Results of a numerical experiment are reported in which key parameters for a system with five coils and a coupled power of 60 kW at the generator frequency 1.76 MHz were assessed. The distributions of temperature, pressure, flow rate, and current and magnetic flux density are displayed. The numerical experiment presented was carried out using the Magnetic Fields, Laminar Flow, and Heat Transfer modules of COMSOL Multiphysics®. [ABSTRACT FROM AUTHOR]

A multielement inductively coupled plasma atomic emission spectrometry (ICP-AES) technique has been proposed for high-speed monitoring of the preparation of pure antimony, and analytical lines of analytes with the weakest spectral effects have been chosen. We have studied the effect of matrix component concentration (5 to 40 g/L) on the analytical signals of impurity elements. Changes in excitation conditions in the plasma at a varied antimony concentration in solution and varied ICP power have been assessed using the ICP robustness. The robustness was evaluated from the intensity ratio of the magnesium ionic and atomic lines. The presence of 40 g/L of antimony in solution has been shown to reduce the ICP robustness by up to 5%. The adequacy of the proposed technique has been confirmed by the standard addition method and comparison with results obtained by an independent method. The proposed technique for analysis of antimony allows one to determine 56 impurity elements with detection limits from n × 10–7 to n × 10–4 wt %. [ABSTRACT FROM AUTHOR]

Agriculture has high requirements for both the quality and quantity of water resources. However, the traditional monitoring methods used in the field of water quality monitoring for agricultural irrigation suffer from issues such as complex operation, low automation, and low efficiency. To address these problems, this study proposes an agricultural irrigation water quality monitoring system based on an inductively coupled plasma optical emission spectrometer and designs the usage process and strategies of the spectrometer according to the characteristics of agricultural irrigation water. The water quality monitoring system can precisely monitor heavy metal elements that may contaminate agricultural irrigation water and eliminate the interference of other impurities. Experimental results show that the system achieves a correlation above 0.999 for the standard curves of five major heavy metal elements, and the signal-to-noise ratio of heavy metal elements reaches 12.56 when the system carrier gas flow rate is 0.8 L/min. Compared to traditional detection methods, the system exhibits higher detection speed, automation, and comparable accuracy, thus demonstrating potential for practical application in the field of water quality monitoring for agricultural irrigation. [ABSTRACT FROM AUTHOR]

The goal of this study was to demonstrate a novel potentiometric technique for the measurement of Cd(II) ion. A new ionophore called [5′‐(ethane‐1,2‐diylbis(sulfanediyl))bis(3‐phenyl‐4H‐1,2,4‐triazol‐4‐amine) (ESPTA)] was prepared and used as an electroactive material in the fabrication of new carbon paste electrode (CPE) for the quantification of Cd(II) ion. The paste was prepared by mixing ESPTA, graphite, graphene, and TCP or o‐NPOE as a plasticizer in different weight percent ratios. The developed electrodes I, II, III, and IV showed divalent Nernstian response of 29.80±0.05, 29.80±0.08, 29.86±±0.04 and 29.75±0.33 mV decade−1 over the concentration ranges of 1.0×10−5–1.0×10−1, 1.0×10−8–1.0×10−1, 1.0×10−6–1.0×10−1 and 1.0×10−7–1.0×10−1 mol L−1 with percentage of (2.65 ESPTA: 66.32 graphite: 31.03 TCP), (2.65 ESPTA: 13.27 graphite : 53.05 graphene : 31.03 TCP), (2.75 ESPTA: 68.68 graphite: 28.57 o‐NPOE) and (2.75 ESPTA: 13.74 graphite : 54.94 graphene : 28.57 o‐NPOE), for electrodes I, II, III, and IV, respectively. In order to improve the performance characteristics of electrodes I, II, III, and IV, response time, the effect of temperature, and pH were examined. The electrodes showed high selectivity for Cd(II) over different mono‐, di‐ or trivalent cations. These modified electrodes were applied for the determination of the concentration of Cd(II) in different real samples like Nido Milk, juice extractions and tap water samples with high percentage recovery. The F‐ and t‐test values showed that there is no statistically significant difference between the results obtained and those from the stated method of inductively coupled plasma. Low standard and relative standard deviation values, good percentage recovery, and modest detection and quantification limitations were all displayed by the electrodes. The outcomes showed the potentiometric method's effectiveness in detecting Cd(II) in actual samples and its potential for use in routine analysis. [ABSTRACT FROM AUTHOR]

The generation of a low-frequency low-pressure inductive discharge with ferromagnetic enhancement of the magnetic coupling between the coil and the plasma is investigated. The main features and advantages of this plasma generation method for surface processing technologies are considered. New experimental data on the electrophysical and dynamic characteristics of ferromagnetic-enhanced low-pressure inductive discharge in argon with the addition of oxygen are presented. It is shown that the radial distribution of plasma parameters in a gas-discharge chamber can be controlled using distributed discharge generation. Significant fluctuations in the electron temperature during the discharge electric field period are found, and the mechanism of their occurrence is analyzed. [ABSTRACT FROM AUTHOR]

For decades, the Buriganga River in Dhaka, Bangladesh, has suffered from persistent pollution, leading to heavy metal contamination in fish samples that poses significant risks to human health. This study conducted an analysis of the whole bodies of various fish species, including Heteropnuestes fossilis, Channa punctatus, Notopterus notopterus Channa striata and Colisa fasciata to examine the concentrations of Chromium, Manganese, Nickel, Copper, Zinc, Arsenic, Cadmium, Barium, and Lead. The analysis was performed using inductively coupled plasma mass spectrometry, revealing notable concentrations of Pb, Ni, Cd, and Zn, with average levels of 6.85, 156.77, 0.41, and 3.37 mg/kg, respectively.Assessment of target hazard quotients for Pb, against recommended benchmark doses of observable effects, indicated levels 2 to 6 times higher than the recommended safety thresholds. The cumulative totals of target hazard quotients across multiple specimens exceeded 2 and, in some cases, reached up to 7, surpassing the safety cutoff of 1. The risk of cancer from Ni and Pb was calculated to be 1 in 10,000 on average for each, classifying it as a moderate risk. Quantitative analysis revealed that heavy metal concentrations of Pb, Ni, Cd, and Zn in most fish samples exceeded reference safety values.Simultaneously, hazard analysis identified critical concerns regarding Pb content in one sample, and cumulative toxin loads in almost every sample were deemed unsafe for regular consumption. In addition to quantitative assessments, a qualitative survey employed observation techniques, focus group discussions, and key informant interviews to investigate consumption behaviors and viewpoints on fish contamination. The results revealed that consumers generally held an enthusiastic attitude towards consuming these fish and were largely unaware of the associated health hazards.

A graphitic digestion method linked with inductive coupled plasma optical emission spectroscopy (ICP OES) instrument was used to determine the levels of trace elements in frozen and chilled chicken samples collected from markets in Jouf city, Saudi Arabia. The current method is innovative because samples are digested using a graphitic digestion system, which is safer, facile sample handling, short time for assessment, and more environmentally friendly than existing procedures. The results revealed that the chilled chicken samples contained higher concentrations of Na, Fe, Cr, and Mn than the frozen samples, which were below detection limit. Furthermore, the Cu, Al, Zn, and Cr contents in some of the analyzed chicken samples were over the maximum permissible limit of international standards, indicating a serious risk to consumers. The estimation of health-risk indicated that trace metal contamination causes health risks to the consumers, but the effect decreases with decreasing the target hazard quotient value in the rank of Cr > Al > Zn > Cu > Mn > Fe, with all values less than 1 except for Cr in chilled chicken. Moreover, the tolerable limit (1 × 10−6) for the carcinogenic risk for Cr in chilled chicken was observed to be exceeded.

Lung cancer (LC) is the leading cause of cancer deaths, and chronic obstructive pulmonary disease (COPD) can increase LC risk. Metallomics may provide insights into both of these tobacco-related diseases and their shared etiology. We conducted an observational study of 191 human serum samples, including those of healthy controls, LC patients, COPD patients, and patients with both COPD and LC. We found 18 elements (V, Al, As, Mn, Co, Cu, Zn, Cd, Se, W, Mo, Sb, Pb, Tl, Cr, Mg, Ni, and U) in these samples. In addition, we evaluated the elemental profiles of COPD cases of varying severity. The ratios and associations between the elements were also studied as possible signatures of the diseases. COPD severity and LC have a significant impact on the elemental composition of human serum. The severity of COPD was found to reduce the serum concentrations of As, Cd, and Tl and increased the serum concentrations of Mn and Sb compared with healthy control samples, while LC was found to increase Al, As, Mn, and Pb concentrations. This study provides new insights into the effects of LC and COPD on the human serum elemental profile that will pave the way for the potential use of elements as biomarkers for diagnosis and prognosis. It also sheds light on the potential link between the two diseases, i.e., the evolution of COPD to LC. [ABSTRACT FROM AUTHOR]

Ion thrusters have acquired extensive applications in the space industry with their advantages of high efficiency, high specific impulse, and long lifetime. To operate a radio-frequency (RF) ion thruster successfully, a high-frequency current must be generated to facilitate the discharge of inductively coupled plasma. In this study, with support of trial and error, it is discovered that the thrust performance of an RF ion thruster depends on not only the RF power but also on other critical parameters, such as the propellant flow rate, ion grids voltages, and RF input power. A surrogate model, namely – the Kriging model, is employed to simplify the estimation and optimization of thrust performance. The thrust and specific impulse are selected to be the crucial metrics for used Kriging models for categorizing all types of propulsions. On the basis of Kriging model simulations, the designed RF ion thruster can achieve a thrust of 1.9 mN, a specific impulse of 1649.5 s, and a thrust efficiency of 48% under a propellant flow rate of 4 sccm, grids' voltage difference of 2500 V, and an RF input power of 40 W. • Kriging model was to simplify the optimization of radio-frequency ion thrust performance. • Thrust performance of RIT depends on the radio-frequency power and other parameters. • The optimal RIT can achieve a thrust of 1.9 mN and a specific impulse of 1649.5 s. • The resulting thrust efficiency fulfills 48% under a propellant flow rate of 4 sccm. [ABSTRACT FROM AUTHOR]

A novel dual-antenna micro plasma thruster (DMPT) driven by radio-frequency (rf) power supply is proposed and characterized experimentally. The Langmuir probe (LP) and the retarding potential analyzer (RPA) are applied to measure the plasma parameters. The results show that compared to the single-antenna, the dual-antenna yields higher electron density, electron temperature, and ion energy. The measurements from the rf I–V probe indicate that the power coupling efficiency for the dual-antenna is about 2.6 times higher than that for the single-antenna. The plasma potential drop in the plume of the DMPT is the reason for the formation of ion beam. The neutral gas temperature is measured by rovibrational ban matching of the first negative band system of ionic nitrogen (N 2 +) for operating powers of 20 W up to 100 W. The total thrust of the DMPT has been calculated by the sum of the ion thrust and the neutral gas thrust. The total thrust at 100 sccm argon flow rate and 100 W rf power is ∼2.23 mN, which indicates an up to 168% thrust gain compared to the cold gas thrust, and a significant 11% total thrust is attributed to the ions' electrostatic acceleration. The specific impulse and thruster efficiency at the above experimental conditions are ∼76 s and ∼0.8%, respectively. These initial results show that the dual-antenna scheme has better performance and is more promising than the traditional single-antenna design for electrodeless micro-electric propulsion. This novel and efficient micro plasma thruster is particularly useful for cubic satellites and scientific experiments in space (such as gravitational wave detection) which require gesture and orbit control of great precision. • The dual-antenna scheme can generate higher plasma density and electron temperature. • The significant phenomenon of higher energy ions was observed in DMPT. • Higher power coupling efficiency in DMPT than that in SMPT. [ABSTRACT FROM AUTHOR]

Regularities of the reflected signal intensity changing in time, recorded by the detector of the laser interferometer with the operating frequency of 670 nm during the inductively coupled plasma reactive ion etching in a Cl2/N2/O2 atmosphere of GaN, p-GaN and AlGaN in AlGaN/GaN and p-GaN/AlGaN/GaN heterostructures has been established by laser interferometry and scanning electron microscopy methods due to the changes in refractive indices and etching rates. During inductively coupled plasma reactive ion etching of GaN and p-GaN layers, the intensity of the reflected signal changes according to a periodic law with the thickness change period of about 144 nm, and for AlGaN layers about 148 nm, which is due to differences in their refractive indices and etching rates. During the crossing of the p-GaN/AlGaN and AlGaN/GaN interface, there is an abrupt change in the intensity of the reflected signal within 2.7–9.5 % for 20–40 s, due to changes in the aluminum concentration, refractive indices, and etching rate at the interfaces. The change in the periodicity of the interferogram, which is accompanied by a jump in intensity when passing through the etching front through the p-GaN/AlGaN and AlGaN/GaN interface, makes it possible to determine the end time of the inductively coupled plasma reactive ion etching of the AlGaN and p-GaN layers using laser interferometry in real time in AlGaN/GaN and p-GaN/AlGaN/GaN heterostructures with two-dimensional electron gas. The obtained results can be used to form microwave and power electronics devices elements which are based on the AlGaN/GaN heterostructures.

Hybrid plasmas have been reported in various areas of research over the last 40 years. However, a general overview of hybrid plasmas has never been presented or reported. In the present work, a survey of the literature and patents is carried out to provide the reader with a broad view of hybrid plasmas. The term refers to several different configurations of plasmas, including but not limited to: plasmas driven by several power sources simultaneously or sequentially, plasmas that have the properties of both thermal and nonthermal plasmas, plasmas that are enhanced by additional energy, and plasmas that are operated in a unique medium. In addition, a way of evaluating hybrid plasmas in terms of the improvement of processes is discussed, as well as the negative impacts that follow the employment of hybrid plasmas. Regardless of what the hybrid plasma in question is composed of, it often poses a unique advantage to its nonhybrid counterpart, whether it be used for welding, surface treatment, materials synthesis, coating deposition, gas phase reactions, or medicine. [ABSTRACT FROM AUTHOR]

Inductively coupled plasma (ICP) source with planar and cylindrical coils is one of the effective methods to generate large-area uniform plasma. The effects of the current ratio and phase difference between the planar and cylindrical coil on the plasma characteristics in the dual antenna ICP source are investigated using a two-dimensional (2D) fluid model. When the planar and cylindrical coil sources are in phase, and their currents are 10 A, the inductive electric field is strengthened in the region between planar and cylindrical coils (i.e., r = 0.18–0.21 m, and z = 0.11–0.13 m) due to the superposition of the electric fields in the same direction from the two coils, which strongly heats the electrons in the large radius area of the reactor. As a result, edge-high profiles of ionization rate, plasma density, and ion flux are obtained. As the planar coil's current increases, the magnitude of the electron density becomes higher, the profiles of the electron density and ion current flux shift from edge-high to center-high due to the enhanced electron heating in the center region, and the best uniform plasma is obtained at 25 A. When both the planar and cylindrical coil currents are maintained at 10 A with the phase shift rising from 45° to 180°, the electric fields from the two antennas act in the opposite direction during the time interval from 1/4 RF period to one RF period, respectively. Moreover, the total inductive electric field becomes weak in the region jointly adjacent to these coils, dominating the plasma generation at the reactor center region. Accordingly, the best uniform plasma is obtained for the case of 135°. In summary, the plasma's nonuniform distribution can be smoothed by adjusting the power ratio and phase difference between planar and cylindrical coils. [ABSTRACT FROM AUTHOR]

This work reports on the (zero-dimensional) global model study of argon plasma chemistry for a cylindrical thruster based on inductively coupled plasma (ICP) whose output has a system of two grids polarized with each other with direct current potential. The global model developed is based on particle and energy balance equations, where the latter considers both charged and neutral species. Thus, the model allows the determination of the neutral gas temperature. Finally, this study also investigated the role of excited species in plasma chemistry especially in the ions production and its implications for propulsion parameters, such as thrust. For this, the study was carried out in two different scenarios: (1) one taking into account the metastable species Arr and Arp (multi-step ionization), and (2) the other without these species (single-step ionization). Results indicates a distinct behavior of electron temperature with radiofrequency (RF) power for the investigated cases. On the other hand, the gas temperature is almost the same for investigated power range of up to 900 W. Concern propulsion analysis, a thrust of 40 mN at 450 W was verified for case (1), which represents a remarkable thrust value for electric thrusters.

A method is proposed for the analysis of trace element concentrates by a thin layer method in combination with inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation (LA). Trace elements concentrates were evaporated on preliminarily prepared areas of a high-purity silicon substrate, after which an LA-ICP-MS analysis was performed. The influence of the LA parameters and the conditions for recording the spectra on the signal of the analytes and the substrate material was studied. The analytical capabilities of the thin layer method in combination with LA-ICP-MS for the analysis of high-purity substances with the preconcentration of trace elements were evaluated. Using an analysis of high-purity nitric acid as an example, it was shown that the limits of detection for analytes in the LA-ICP-MS analysis of trace element concentrates using the thin layer method are in the range from n × 10–11 to n × 10–8 wt %. Thus, the development of combined procedures of analysis, including the preconcentration of trace elements and an analysis of concentrates by LA-ICP-MS, makes it possible to reduce the limits of detection for most analytes by one order of magnitude compared to instrumental ICP-MS analysis. [ABSTRACT FROM AUTHOR]

We study the effect of low-energy ion bombardment on the texture and structure of an 80-nm-thick platinum film deposited at room temperature. The film is treated in an inductively coupled Ar plasma with a negative voltage of 45–125 V applied to the samples and an ion-current density of 3.3 mA/cm2. A series of treatments at each voltage results in thinning of the film; after each treatment, its structural parameters are determined by X-ray diffraction analysis and compared with the parameters of Pt films 20–60 nm thick deposited under the same conditions. The treatment at 75–125 V decreases the average size of the coherently diffracting domains by 10–25%; at 45 V, such a decrease is not observed. The results are explained by the formation and accumulation of radiation defects; the rate of their formation is lower at 45 V. Film sputtering in all modes does not worsen the sharpness of the film texture. [ABSTRACT FROM AUTHOR]

A graphitic digestion method linked with inductive coupled plasma optical emission spectroscopy (ICP OES) instrument was used to determine the levels of trace elements in frozen and chilled chicken samples collected from markets in Jouf city, Saudi Arabia. The current method is innovative because samples are digested using a graphitic digestion system, which is safer, facile sample handling, short time for assessment, and more environmentally friendly than existing procedures. The results revealed that the chilled chicken samples contained higher concentrations of Na, Fe, Cr, and Mn than the frozen samples, which were below detection limit. Furthermore, the Cu, Al, Zn, and Cr contents in some of the analyzed chicken samples were over the maximum permissible limit of international standards, indicating a serious risk to consumers. The estimation of health-risk indicated that trace metal contamination causes health risks to the consumers, but the effect decreases with decreasing the target hazard quotient value in the rank of Cr > Al > Zn > Cu > Mn > Fe, with all values less than 1 except for Cr in chilled chicken. Moreover, the tolerable limit (1 × 10−6) for the carcinogenic risk for Cr in chilled chicken was observed to be exceeded. [ABSTRACT FROM AUTHOR]

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At RF plasma reactors operated at high power, internal Faraday shields are required to shield dielectric vessel or windows from erosion due to isotropic heat and particle fluxes. By utilizing a flexible and diagnostically well-equipped laboratory setup, crucial effects that accompany the application of internal Faraday shields at low-pressure hydrogen (and deuterium) RF discharges are identified and quantified in this contribution. Both an inductively coupled plasma (ICP) utilizing a helical coil and a low-field helicon discharge applying a Nagoya-type III antenna at magnetic fields of up to 12 mT are investigated. Discharges are driven at 4 MHz and in the pressure range between 0.3 and 10 Pa while the impact of the Faraday shields on both the RF power transfer efficiency and spectroscopically determined bulk plasma parameters (electron density and temperature, atomic density) is investigated. Three main effects are identified and discussed: (i) due to the Faraday shield, the measured RF power transfer efficiency is globally reduced. This is mainly caused by increased power losses due to induced eddy currents within the electrostatic shield, as accompanying numerical simulations by a self-consistent fluid model demonstrate. (ii) The Faraday shield reduces the atomic hydrogen density in the plasma by one order of magnitude, as the recombination rate of atoms on the metallic (copper) surfaces of the shield is considerably higher compared to the dielectric quartz walls. (iii) The Faraday shield suppresses the transition of the low-field helicon setup to a wave heated regime at the present conditions. This is attributed to a change of boundary conditions for wave propagation, as the plasma is in direct contact with the conductive surfaces of the Faraday shield rather than being operated in a laterally fully dielectric vessel.

Measurements of ion flux-energy distribution functions at the high sheath potential of the driven electrode in a classical low-pressure asymmetric capacitively coupled plasma are technically difficult as the diagnostic device needs to float with the applied radio frequency voltage. Otherwise, the ion sampling is disturbed by the varying electric field between the grounded device and the driven electrode. To circumvent such distortions, a low-pressure plasma chamber with inverted electrode geometry, where the larger electrode is driven and the smaller electrode is grounded, has been constructed and characterized. Measurements of the ion flux-energy distribution functions with an energy-selective mass spectrometer at the high sheath potential of the grounded electrode are presented for a variety of conditions and ions. The potential for suppressing low-energy ions from resonant charge transfer collisions in the sheath by the dilution of the working gas is demonstrated. Additionally, the setup is supplemented by an inductively coupled plasma that controls the plasma density and consequently the ion flux to the substrate while the radio frequency bias controls the ion energy. At high ion energies, metal ions are detected as a consequence of the ionization of sputtered electrode material. The proposed setup opens a way to study precisely the effects of ion treatment for a variety of substrates such as catalysts, polymers, or thin films.

Aiming at the discharge problem of inductively coupled plasma (ICP), a closed wave-transmitting cavi-ty configuration is designed, the fluid mechanics model of ICP is established, and the multi physical simulation software COMSOL is used for three-dimensional simulation research. The variation laws of typical parameters such as electron density, electron temperature and plasma potential with time in the discharge process are analyzed. On this basis, the power of radio frequency power supply, the air pressure in the cavity and other conditions are changed to obtain the parameter range and spatial gradient distribution of ICP. The results show that the discharge power mainly affects the numerical range of plasma parameters, and the change of air pressure has an effect on the numerical value and spatial distribution of plasma parameters. When the power of radio frequency power supply increases from 100 W to 300 W, the peak electron density increases from 2.54×1017 m-3 to 5.68×1017 m-3, and the electric potential induced in the heating zone and the corresponding electron temperature decrease slightly after the reaction is stable. Increasing the air pressure in the cavity within a certain range will significantly increase the electron density. The air pressure increases from 10 Pa to 30 Pa, and the electron density increases from 9.12×1017 m-3 to 3.62×1018 m-3. However, the uniformity of plasma parameter distribution will deteriorate if the air pressure is too high.

Inductively coupled plasma or ICP sources form a basis for multiple applications ranging from semiconductor fabrication to reliable heating systems for tokamak machines. To meet the functional requirements, ICP sources need efficient plasma formation utilizing the various input parameters. Operation of ICP sources is a complex and challenging task since it involves scanning a wide multi-dimensional parameter space involving filament bias, radio frequency (RF) power, gas pressure, matching parameters, and other system configurations. The foremost challenge is to maximize the coupling of RF power in the ion source for efficient plasma formation. Standard ICP sources use a matching network that consists of variable capacitors to compensate for plasma inductance to enable maximum power coupling. Identification of an accurate set of matching parameters for high power sources is a complex task and is generally driven by operator experience which is established after years of operations. Due to these challenges, recent developments in the area of machine learning can be utilized for identifying the underlying model function to make accurate predictions and explore an alternative approach to the existing Physics-electrical models developed for the estimation of matching parameters for plasma sources. The present work attempts to perform a data-driven model discovery for the identification of appropriate matching parameters utilizing machine learning algorithms. In this work, ROBIN, a high-power ICP source that operates with a 1MHz, 100 kW RF generator is considered which has been operational since 2011 and has generated a considerable database. This database can be utilized for training/developing data-driven models for the estimation of matching parameters for ensuring better power coupling. The paper describes the development of two data-driven regression models for predicting the coupling efficiency in terms of power factor (denoted by Cos ϕ) and the capacitor values based on input parameters utilizing well known algorithms such as support vector machine, random forest and neural networks. Emphasis has been laid on developing the models using parameters that are tuneable externally. Also, the effect of system configurations on parameter prediction is investigated. The developed machine learning-based models have achieved test accuracy scores of 0.93 and 0.91 for predicting Cos ϕ and capacitor values respectively. The paper presents the training and optimization process for various machine and deep learning algorithms in detail. • Estimation of matching parameters for RF plasma in an ICP source using ML is explored. • Various ML algorithms are compared for predictive modelling of parameters. • Optimization techniques for tuning ML and Neural network-based model are presented. • Mode based performance is explored for trained models. [ABSTRACT FROM AUTHOR]

Plasma anisotropic etching polishing (plasma-AEP), a non-contact polishing method, is proposed to achieve highly efficient planarization of polycrystalline diamond (PCD) films. Inductively coupled plasma, with a high concentration of reactive radicals, serves as the source of plasma-AEP. In-situ observation confirms that the planarization effect of plasma-AEP is realized through the preferential removal of the top areas of the pyramid-shaped protrusions, despite the entire surface being uniformly irradiated by the plasma. The material removal rate in plasma-AEP for PCD achieves 127 μm/min. Plasma-AEP is proven effective for PCD films with thicknesses of 0.5, 1, and 2 mm, demonstrating a generic semi-finishing approach for PCD regardless of thickness. Atomic-scale nudged elastic band calculations revealed that the energy barriers for CO and CO 2 desorption from 1- and 2-coordinated C atoms are significantly lower than those for 3- and 4-coordinated ones. ReaxFF molecular dynamics simulations showed that at the top areas of the pyramid-shaped protrusions, 1- and 2-coordinated C atoms with a higher etching priority remained dominant during plasma-AEP, leading to the preferential removal of C atoms forming these protrusions. Furthermore, contact polishing was added to complete the finishing of the PCD film, followed by plasma-AEP, resulting in a nanoscale smooth surface with a roughness of 3.4 nm. Transmission electron microscopy confirmed that the crystal structures on the surface and subsurface of the PCD film were well ordered. Overall, this paper displays that plasma-AEP is a promising approach for highly efficient semi-finishing of PCD films. [Display omitted] • Plasma anisotropic etching polishing (plasma-AEP) is developed. • Preferential removal of protrusions on polycrystalline diamond (PCD) is confirmed. • The anisotropic etching characteristic is revealed by multi-scale simulations. • Plasma-PAE is generic for semi-finishing PCD with various thicknesses. • Contact polishing is added to achieve nanoscale finishing of PCD. [ABSTRACT FROM AUTHOR]

Gallium nitride (GaN) surface microstructures are crucial for enhancing the performance and reliability of high-power devices. However, the direct fabrication of patterned three-dimensional (3D) microstructures on GaN surfaces remains a significant challenge. This paper introduces an innovative approach, employing a maskless femtosecond laser combined with inductively coupled plasma (ICP) etching, to efficiently fabricate petal-shaped 3D microstructures on GaN surfaces. By fine-tuning the ICP etching and femtosecond laser parameters, we have obtained the regularities of the dimensional variations of these 3D microstructures. Additionally, our investigation reveals that the design of microstructural concavity and convexity characteristics can be flexibly manipulated by controlling the ICP etching rate, which is influenced by the oxide content in the laser-modified zone. This study presents a novel method for straightforward fabrication of microstructures on gallium nitride surfaces. • 3D microstructures fabricated on GaN surface by ICP-assisted femtosecond laser. • Microstructure dimension controlled by pulse, laser energy, ICP parameters. • Flexible design of 3D microstructures for concavity and convexity realized. [ABSTRACT FROM AUTHOR]

In this study, multi-walled carbon nanotubes (MWCNTs) were incorporated as functional fillers into bitumen emulsion, along with self-sensing cementitious sensors, to investigate their internal curing and ion conduction. The mechanical properties, piezoresistivity, moisture content, and internal curing of cementitious sensors were analysed under different MWCNTs and water contents. Isothermal Calorimetry (IC), Nuclear Magnetic Resonance (NMR), Thermogravimetric Analysis (TGA), and Inductively Coupled Plasma (ICP) methods were employed to supplement the findings and unveil the mechanism. The compressive strength of bitumen-cement mortars was found to be comparable to that of the counterpart cement mortars. The results confirmed that bitumen emulsion improved the piezoresistivity due to the increased water content in the mortars and the influence of micro-holes. Additionally, the bitumen emulsion limited the moisture loss, leading to improved internal curing. The piezoresistivity was observed to be affected by ion conduction, which in return was influenced by water content. Moreover, as water content of self-sensing mortar decreased, the piezoresistivity initially increased and then decreased, flowing the moisture loss rate. These outcomes can offer insights into the performance of self-sensing bitumen cementitious sensors and their potential application in traffic condition detection and road health monitoring. [ABSTRACT FROM AUTHOR]

In this work, AlGaN with a GaN cap has been etched in a cyclical process with ICP-RIE O 2 plasma oxidation and wet etching in dilute HCl. The oxygen plasma ICP-RIE etching of the AlGaN at an ICP plasma power of 200 W and radio frequency bias power of 100 W led to an etch depth of ∼1.5 nm per digital cycle with increased surface roughness. The AlGaN remained unaffected by the wet etching process alone without any ICP-RIE O 2 plasma oxidation, maintaining a surface roughness similar to that of the substrate. AlGaN was etched to a depth of ∼12 nm after six cycles of digital etching with an etch rate of 1.9–2.1 nm/cycle showing an improved surface roughness. The XPS analysis at each stage of the etching process reveals that the O 2 plasma oxidation initially oxidizes the GaN cap and the AlGaN layer and is later effectively removed by the HCl solution. The digital etching method has proven effective in controlling etch depth and surface roughness, which are needed to fabricate AlGaN high electron mobility transistors. [Display omitted] • Two step digital etching of AlGaN/GaN heterostructure with GaN cap. • Surface morphology was analyzed using AFM technique after the six digital etch cycles. • Chemical bonding analysis was carried out by XPS after digital etching process. • TEM analysis was employed for digitally etched AlGaN surface for six digital cycles. [ABSTRACT FROM AUTHOR]

Global modeling of inductively coupled plasma (ICP) reactors is a powerful tool to investigate plasma parameters. In this article, the argon ICP global model is revisited to explore the effect of excited species on collisional energy through the study of different approaches to particle and energy balance equations. The collisional energy loss is much more sensitive to modifications in the balance equations than the electron temperature. According to the simulations, the multistep ionization reduces the collisional energy loss in all investigated reaction sets and the inclusion of heavy species reactions has negligible influence. The plasma parameters obtained, such as total energy loss and electron temperature, were compared with experimental results from the literature. The simulated cases that have more excited species and reactions in the energy balance are in better agreement with the experimental measurements.

The concentrations of elemental and volatile components in wine and the effect of biological, meteorological, and anthropogenic factors on their levels are important for authentication and quality assurance. Sample preparation for atomic absorption and inductively coupled plasma spectrometries for elemental analysis as well as chromatographic and electronic nose (EN) analytical methods for volatile compounds are reviewed. The International Organization of Vine and Wine (OIV) and countries that produce and import wine developed methods and set limits on metal abundance to ensure that all metal concentrations are well below toxic threshold limits. With the use of data analysis tools, elemental analysis can enable wines to be traced back to their geographic region of origin. When paired with volatile and isotopic analysis the accuracy of this authentication greatly improves. Tracing studies are reviewed to demonstrate the capabilities of these analyses. [ABSTRACT FROM AUTHOR]

With the growing demands for transferring large amounts of data between components in a package, it is required for advanced packaging technologies to form smaller vertical vias in the insulators. Plasma etching is one of the most widely used micro-vias formation processes. This paper has developed a fabrication process for 5–10 µm residue-free micro-vias with 70° tapered angle in polyimide film based on O2/CHF3 inductively coupled plasma (ICP). The etch rate would monotonically increase with the ICP power, RF power, and gas flow rate. As for the gas ratio, there is an optimum range of CHF3 ratio, which could obtain the highest etch rate. The results have clearly shown that the enhancement of ion bombardment and prolongation of etching time would be beneficial to grass-like residue removal. In addition, during the etching of partially cured polyimide, the lateral etch rate would significantly increase in the region near the metal hard mask. [ABSTRACT FROM AUTHOR]

This paper presents a physics-based 0-D steady-state model of a radiofrequency ion thruster (RIT) that is valid for any propellant blend, and hence, any plasma mixture, and the model is used to predict the drag compensation capability and plasma composition of an air-breathing RIT operating in very-low Earth orbit (VLEO). This study fills a gap in the modeling of air-breathing electric propulsion with an air-breathing RIT model that is validated with experimental data of a RIT operating with an N 2 / O 2 mixture. The model expands upon current 0-D RIT models by accounting for the dissociation of neutral molecules and molecular ions and by applying particle conservation for each ion and neutral species. Atomic oxygen in the atmosphere is assumed to completely recombine into O 2 in the collector, and the model is used to calculate an air-breathing RIT's thrust, discharge efficiency, mass utilization efficiency, and discharge plasma composition at altitudes between 80 and 150 km. At 1 kW of total input power and an optimal flow rate of 0.17 mg/s, the net thrust was limited to 3 mN at all altitudes considered. At these same operating conditions, the mass utilization efficiency and discharge efficiency were approximately 0.15 and 870 eV/ion, respectively. To increase the performance of the thruster, the magnetic field should be increased in order to increase the beam current. The mole fraction of atomic oxygen in the discharge chamber was found to be between 0.19 and 0.27 depending on the altitude, indicating that grid erosion should be a focus of future studies. [ABSTRACT FROM AUTHOR]