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The boron-10 ion implantation in layers on the core components can provide lower nuclear reactivity due to an abnormally large neutron-capture cross-section during the initial stage of the reactor operation. It is shown that after the boron-10 ion implantation at 22 keV energy with 7∙1016 ion/cm2 fluence, the surface microhardness of E110 zirconium alloy increases from 3 to 3.7 GPa. After the boron-10 ion implantation in the indicated conditions (22 keV energy and 7∙1016 ion/cm2 fluence), the corrosion rate of E110 zirconium alloy in a 1% hydrofluoric acid solution is 1.2–1.4 times lower than that of the nonimplanted alloy. The boron-10 ion implantation is accompanied by such processes as the formation of a subgrain structure in the surface layer of the alloy, the grain size of which ranges within 100–200 nm; the increase in the scalar dislocation density; and the formation of 1.8–2.3 nm nanoparticles of zirconium boride.

The article presents the results of recent experimental studies of spontaneous electron beam modulation with a frequency of several tens of megahertz in a plasma-filled diode. The diode comprises a plasma cathode with a grid-stabilized emission boundary and a plasma anode with an open (conditionally electrodeless) movable boundary. The cathode plasma is formed by a cathodic arc and the anode plasma by toroidal plasma generators based on an anode-layer closed drift thruster. According to our previous studies, the beam current starts to modulate as the arc current goes above 50–55 A at an accelerating voltage of 12–22 kV. Here, we analyze how such electron beam modulation and its frequency are influenced by the grid geometry at a current of about 100–110 A and what methods can be used for its removal. The idea of removal consists in decreasing the effect of the accelerating voltage on the cathode plasma, for example, via a negative current feedback. It is shown that the most efficient modulation suppression is attained when the negative feedback is frequency-dependent and that the modulation frequency decreases to its complete disappearance as the grid mesh size is decreased.

The principle of operation and the characteristics of the experimental equipment intended for the generation of boron ion plasma and beams are presented. The equipment comprises a vacuum arc source of boron ions with boron isotope separation in a magnetic field and a plasma generator for deposition of boron-containing coatings based on a planar magnetron sputter. Common to this equipment is the use of lanthanum hexaboride cathodes, but for planar magnetron, a pure boron cathode heated in the discharge is also used. It is shown that, when silicon wafer is implanted with beams of 10B+ and 11B+ boron isotope ions with doses of 1014–1016 ion/cm2, the isotopic effect of the diode properties of the implanted surface is observed. The results of studies of the properties of the obtained boron-containing coatings on model materials: stainless steel, crystal silicon, and E110 (Zr–1Nb) reactor alloy are presented.

The urgency of the study of generation of beams and plasmas containing boron ions is caused by their application in ion-beam and plasma technologies of modification of the surface properties of not only semiconductors, but also structural materials. This is due to the fact that boron compounds are hard and chemically resistant materials that can be used to create hardening and protective surface coatings for a wide nomenclature of details. The operating principle and the characteristics of the experimental setup developed for generation of plasma and boron ion beams intended for creation of such coatings are presented, including an ion source based on vacuum arc with separation of boron isotopes in a magnetic field intended for highdose ion implantation, a plasma generator with boron target intended for obtaining coatings by magnetron sputtering, and a forevacuum electron source intended for synthesis of surface boron-containing coatings by electron beam evaporation.

The paper reports on recent experimental studies of the operation of a vacuum arc ion source with a hot pressed lanthanum hexaboride (LaB6) rod cathode which has a low porosity and almost perfect density (4.65 g/cm3). Under normal conditions the resistivity of LaB6, being a refractory ceramic material, is very low and its conductivity is similar to that of metals, and the behavior of cathode spots on the surface of LaB6 is the same as their behavior on pure metals. From cathode spots, the vapors, charged particle flows, a large flow of macroparticles and small cathode fragments is emitted. Such macroparticles bombard the electrodes of the ion-optical system of the source and evaporate, forming a dense plasma, with the result that the acceleration gap is broken down within several milliseconds after vacuum arc extinction. For reducing the flow of macroparticles, the discharge system of the source is equipped with a mechanical direct-flow filter in the region of cathode plasma expansion. The loss of plasma in the filter is compensated by the fields of a permanent magnet and solenoid. The vacuum arc source produces a pulsed (about 300 μs) boron–lanthanum ion beam with a current of 600 mA and diameter of 4 cm with no gas supply.

By the example of an inhomogeneous electromagnetic wave formed by the superposition of two plane monochromatic electromagnetic waves, which are arbitrarily directed relative to each other, an approach is demonstrated that makes it possible to simulate a broad spectrum of electromagnetic waves. The complete set of equations describing the motion of an electron in an inhomogeneous electromagnetic field is solved numerically. The features of the trajectory and emission spectrum of the electron are found and investigated.

This is a brief review of the current status of study and progress in devices for a new generation of plasma-dynamic tools based on combining a vacuum-arc plasma source with an axially symmetric cylindrical electrostatic plasma-optical lens into a single device. The combined system operates using the basic plasma-optical principles of magnetic electron isolation and equipotentialization along magnetic field lines and could be attractive for many practical applications of high current, moderate energy plasma sources of heavy metal ions and electrons. The hardware is relevant to processing equipment using dense cleaned plasma streams for the synthesis of coatings and thin films with given functional properties. A combination of the plasma lens with vacuum-arc ion plasma sources like the MEVVA allows control of low-energy dense plasma flow from the cathode spot region toward the substrate (for film deposition) or toward an extraction system (for ion beam generation). The application of the plasma lens for the transport of low-energy plasma is shown to improve plasma delivery to a substrate and provide microdroplet evaporation and elimination by fast electrons within the lens region. These results open up a new and attractive way for further development and application of erosion plasma sources for the synthesis of functional coatings, as well as for the creation of upgraded vacuum-arc ion sources with improved characteristics.

Application of ultrawideband centimeter-wavelength signals using recirculation of signals in spatial recirculation loops (emitter–target–element of the receiving antenna–emitter) is analyzed in the problem of localization of the position of a point object above a reflecting metal surface. Determination of the coordinates of object above a metal surface is based on the calculation of a generalized correlation integral in the spectral domain for frequency transmission coefficients of the recirculation loops over all receiving elements with allowance for coordinates of a true object, its mirror reflection, and reference point in space. The results of sounding in the presence and absence of the recirculation are compared.

We have explored the influence of supplementary electron injection on the operational parameters of a planar magnetron operating in repetitively pulsed mode (repetition rate 300 Hz, pulse duration 50–100 μs). The supplementary electron flux was provided from the plasma of an auxiliary hollow-cathode glow discharge and was accelerated directly into the magnetron cathode layer. We show that this supplementary electron injection eliminates magnetron ignition delay and increases the sputtered ion current from the magnetron plasma.

Experiments are reported demonstrating the generation of a wide-aperture electron beam with high-frequency modulation in a plasma-cathode electron source with a diode-type bipolar plasma-filled optical system. The plasma optical system is formed by a plasma cathode (plasma electron emitter) with a grid-stabilized emission surface and a lengthy plasma anode with an open movable plasma boundary. The system with its low impedance and high perveance can provide the required electron beam power density at a relatively low accelerating voltage (tens of kilovolts). The plasma in its anode region is produced by a plasma dynamic device based on a closed drift accelerator. The plasma cathode presents a hollow plasma electron emitter with a vacuum arc plasma generator on the inside. The electron source operates in repetitive pulsed mode at a pulse duration of $100 \ \mu\mathrm{s}$ , pulse repetition frequency of 10 pps, and electron emission current of up to 140 A. The experiments show that the beam in the acceleration gap of the plasma optical system gets into high-frequency modulation mostly at an accelerating voltage of $10\div 20\ \mathrm{kV}$ and arc current greater than 60 A. High-frequency modulation is also observed in the emission current with no plasma in the anode region of the plasma optical system. The basic modulation frequencies are about 18 and 54 MHz.

A boron ion plasma can be used to form monoisotopic ion beams containing 100% of ${}^{10}B+$ or ${}^{11}B^{+}$ ions. In the present work, we study one of the methods that is used to generate such plasmas and which is based on a vacuum arc discharge with a lanthanum hexaboride cathode. Using an ion source based on a vacuum arc discharge and a magnetic separator, we obtained compositionally uniform ion beams of boron isotopes with atomic masses 10 and 11 a.m.u. We performed a separate implantation of ${}^{10}B^{+}$ and ${}^{11}B^{+}$ ions on silicon and zirconium-niobium alloy surfaces with exposition doses up to $5\cdot 10^{15}\ \text{cm}^{-2}$ . The secondary ion mass spectroscopy (SIMS) technique was used to study the implantation profiles of subsurface areas of the materials treated by ion beams. Using identical operation conditions of the vacuum arc as in the case of the ion implantation, the cathode erosion products were deposited on a silicon surface. The scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDS) techniques were employed to analyse the surface microstructure of the cathode and deposited coating as well as their elemental composition.

The article presents recent results of the dramatically enhanced electric breakdown strength observed in the accelerating gap of a plasma-filled optical system for the formation and focusing of a wide-aperture pulsed electron beams with currents up to 80 A and energies up to 35 keV. This system is a plasma-optical diode type device in which the acceleration and formation of the electron beam occurs in the double layer between the emissive surface of the plasma cathode (electron emitter) stabilized by a fine mesh grid and the open surface of the anode plasma. The anode plasma is created by the toroidal plasma generator of original design based on the ion source with closed drift of electrons with an anode layer.

Generation of high charge state metal ions in arc plasma is investigated and methods of elevation of the average ion charge state are analyzed. To realize multiple ionization of the arc plasma, a strong magnetic field in the arc cathode area, an ark current spike, an injection of a high-current electron beam or a high-power microwave radiation flow into the plasma, and a creation of a short high-current arc are realized. For each method, the main features are considered and the maximum ion charge states are determined.

We have explored the operation and characteristics of a planar magnetron discharge system with central on-axis electron injection and a reflector electrode. The diameter of the magnetron copper target was 125 mm; the operating gas was argon and the pressure range 2 × 10−4 – 2 × 10−3 Torr. To increase the efficiency of electron injection, a negatively-biased reflecting electrode was located on the system axis. We have investigated the effect of the reflector electrode on the characteristics of the magnetron discharge, as a function of reflector shape, cross-sectional area, electrical bias, and distance from the target. It is shown that the simultaneous use of central injection of electrons with their acceleration across the cathode layer of the magnetron discharge, and a cone-shaped reflector electrode allows the current to be increased and the operating pressure to be decreased by a factor of several for a fixed magnetron discharge voltage.

We describe our work on tungsten disilicide film deposition by planar magnetron sputtering at low operating gas pressure (down to 0.08 Pa). The sputter target was a tungsten disilicide composite with diameter 125 mm, and the DC magnetron current 0.1–1 A. We have explored the dependence of film homogeneity over the 100 mm diameter substrate on substrate temperature and distance from the magnetron, and the spatial distribution of ion current density and the effect of operating pressure on the roughness and resistivity of the films.

The characteristics of a magnetron discharge system enhanced by the supplementary injection of energetic electrons are presented. Two versions of a two-stage arrangement were explored: central electron injection and peripheral injection into the cathode layer from an auxiliary glow discharge located downstream of the plane of the sputter target. Electrons injected form the auxiliary discharge are accelerated in the cathode layer of the magnetron discharge to an energy sufficient for effective gas ionization and formation of dense plasma near the sputter target. The minimum operating pressure of the non-self-sustained magnetron discharge is 4 × 10 −2 Pa at a discharge current of up to 400 mA. The two different embodiments, with central and peripheral electron injection, show stable operating modes differing in discharge voltage and plasma parameters.

The effect of operating pressure in the ultra-low range (down to 7 × 10−2 Pa) on film deposition by planar magnetron sputtering using a copper target has been studied. The magnetron discharge power was 500 W (target diameter 125 mm) in DC mode. The distance from the target to the deposition substrate was varied from 25 to 55 cm. The axial distribution of plasma ion current density and ion mass-to-charge ratio were measured under the same conditions by a moveable Langmuir probe and a modified quadrupole mass spectrometer, respectively. The influence of working gas pressure on film parameters such as deposition rate and roughness was investigated.

We have investigated an atmospheric pressure discharge in the argon flow using magnesium, zinc, and boron carbide electrodes and determined the conditions for emission of the aerosol consisting of cathode material nanoparticles suspended in the gas mixture of argon and air. It has been experimentally demonstrated that for the discharge operating in the pulsed mode at a frequency up to 100 kHz and mean power up to 80 W, below the current level required for the transition to atmospheric pressure arc with cathode spots (from several milliamperes to 0.5 A), there exists an operating regime under which the cathode material takes part in the discharge maintenance and formation of the plasma flow. The coatings, produced as a result of aerosol condensation, have been studied using scanning and transmission electron microscopy. Elemental composition of the coatings has been studied using an energy-dispersion spectrometer. With the help of the employed techniques, we have determined that the coatings consist of nanoparticles, of the sizes varying from several to tens of nanometers, agglomerated in larger particles that include, in approximately equal parts, atoms of the cathode material and oxygen. The obtained result opens up new possibilities in generation of combined gas-metal flows under atmospheric pressure for the purpose of producing ultra-disperse powders.

We describe the results of our work on enhanced electric breakdown strength observed in the plasma-anode bipolar optical system of a plasma-cathode electron gun. This kind of optical system uses a plasma-filled diode in which the acceleration and formation of the electron beam occurs in the double layer between the emission surface of the plasma cathode, stabilized by a fine-grained mesh, and the open surface of the anode plasma. The anode plasma is created by self-contained gas-discharge plasma sources whose original design was based on a plasma thruster with anode layer. The parameters of the plasma source are almost independent of the electron beam parameters, and its use in an electron gun enhances the breakdown strength of the acceleration gap and nearly doubles the electron beam current. The thruster-based plasma optical system (POS) resolves the anode grid problem and opens the way to controllable plasma-filled wide-aperture POS. We show that the POS can be effectively used for large-area electron beam formation.

We describe recent results of our investigations of a repetitively pulsed vacuum arc plasma source with pure boron cathode. Boron is a semiconducting material with high specific resistance (about 1.8 MOhm.cm) under normal conditions. The high resistance and strong temperature dependence of the boron cathode material determine the features of the arc discharge ignition and cathode spot behavior. For arc ignition with pure boron, it is necessary to preheat the cathode up to 1000 °C. Here we describe a novel arc triggering technique that allows cathodic arc operation with pure boron while the cathode temperature is only about 600 °C. Our vacuum arc ion source produces a 450 mA pulsed ( $100-300 \mu{\mathrm{m}}$ ) space-charge compensated beam of boron ions of singly- and doubly ionized charge states with no gas and few impurity atoms. The arc discharge current was up to 100 A. We have investigated the discharge and basic characteristics of the boron plasma source using two cathode samples made by casting and hot pressing.

The paper presents the results of recent experimental research in a wide-aperture plasma optical system (POS) based on a closed drift anode layer thruster. The thruster serves as a toroidal gas discharge source of anode plasma and provides a high ionization probability and a high plasma density at relatively low gas flow rates and low gas pressures. The parameters of the plasma source are controllable and almost independent of the electron beam parameters, and its use in an electron gun enhances the breakdown strength of the acceleration gap and nearly doubles the electron beam current. The thruster-based POS resolves the anode grid problem and opens the way to controllable plasma-filled wide-aperture POS.

A combined system including a MEVVA plasma source with a cylindrical electrostatic plasma-optical lens is considered for the first time. This combined system is of fundamental interest and could be attractive for a number of practical applications. The system can be used for effective repetitively pulsed, high current, moderate energy plasma sources of heavy metal ions and electrons. The hardware is interesting for high productivity technological equipment using dense pure plasma flow for the synthesis of fine coatings and thin films. We have studied the plasma-dynamic characteristics of high density plasma flow propagating through the plasma lens, the optical emission spectra and the charge state distribution, as a function of different experimental conditions. Application of the plasma lens to the transport of low energy high-current ion beams can improve the delivery of plasma to a substrate, as well as providing micro-droplet evaporation and elimination due to the presence of fast electrons within the lens region.

We have investigated an atmospheric pressure discharge, similar to a plasma jet, in the N2 and CO2 gas flows. We have also carried out an experimental modeling with the argon Ar flow. It has been shown that the use of a tantalum cathode and a copper anode provides a stable discharge in the nitrogen and carbon dioxide flows. We have studied the dependence of the discharge voltage on the discharge current (VAC). Optical emission spectra of discharge glow was investigated also. Using a single probe and a thermocouple, we have studied the axial distribution of the floating potential in the plasma jet and the gas temperature at the anode nozzle exit of the plasma generator. In applying to polymer surface modification, we have determined the optimal operation conditions: gas flow rate up to 5 l·min−1; continuous or pulsed working regime; discharge current about 80 mA; pulse duration up to 10 µs; pulse repetition rate 50 kHz.

The conceptual design of pulsed plasma source for plasma-optic application and materials modification are investigated. The source is based on plasma thruster’s technology, that were developed by Goncharov’s group in Institute of Physics (Kiev, Ukraine). The plasma device with its two modified closed-drift anode layer thrusters can operate in low-current high-voltage mode and in high-current plasma mode. Most attention in the paper is focused on the latter mode being similar to a glow discharge with a positive column. The study shows that under certain conditions, the discharge with closed electron drift can be accompanied by non-self-sustained hollow-cathode discharges with oscillating electrons which greatly decrease the auxiliary discharge voltage. Presented in the paper the current–voltage characteristics of this type of high-current discharge and the spatial distributions of plasma parameters are measured in the discharge region with double Langmuir probe techniques. The maximum plasma densities on the central cathode axis are (6.5÷6.8)×1012 cm–3.

The report presents experimental research results on a pulsed vacuum arc discharge with a cathode made of commercially available boron. The unique properties of boron make it attractive as a coating material, and many studies are now pursued to investigate different discharge systems with sputtering of boron-containing targets [1–3]. Boron is a wideband-gap semiconductor having a high specific resistance $( \sim 1.8$ MOhm $\times $ cm) under normal conditions. Because of the so high resistance, the initiation of an arc discharge with a pure boron cathode requires preliminary heating of the cathode to temperatures above $600^{\circ}\mathrm {C}$. The discharge is initiated by a flashover of an alumina ceramic insulator separating the cathode and trigger electrode.

The results of investigation of the sheet resistance of alumina ceramic as a function of the fluence of implanted metal ions are presented. Tantalum ions with the average energy about 145 keV were used in experiments. Estimation of the sheet resistance was performed from analysis of volt–ampere characteristics by measuring the leakage current at a voltage between 100 V and several kilovolts, which was applied at a small area of the implanted surface. Energy dispersive X-ray analysis was used to determine composition of elements in the surface of the implanted ceramics. As a practical application of research results, it was shown that, after the creation of a weak conducting layer on the surface of the ceramic insulator, the electric field strength of the flashover increases by more than 25%.

Boron ions can be implanted not only in semiconductors such as silicon wafers but also in other materials and metal products, e.g., machine parts and tools, to increase their surface properties and therefore lifetime. The purity of boron ion beams for these purposes is not so critical as for semiconductor technologies. Here, we present experimental results on the generation of pulsed boron ion beams in vacuum arc and planar magnetron ion sources with pure boron and lanthanum hexaboride cathodes with emphasis on the mass-charge state composition of the ion beams.Boron ions can be implanted not only in semiconductors such as silicon wafers but also in other materials and metal products, e.g., machine parts and tools, to increase their surface properties and therefore lifetime. The purity of boron ion beams for these purposes is not so critical as for semiconductor technologies. Here, we present experimental results on the generation of pulsed boron ion beams in vacuum arc and planar magnetron ion sources with pure boron and lanthanum hexaboride cathodes with emphasis on the mass-charge state composition of the ion beams.

In this paper, we present the research results on focusing and transport of an intense (up to 100 A) nonrelativistic (up to 20 kV) pulsed electron beam using an axially symmetric device with a high-current plasma lens configuration. The electron source is based on electron extraction from the plasma of a hollow-anode vacuum arc discharge. The arc is initiated by a dielectric surface flashover. The emission hole is covered with a fine mesh grid. The beam is extracted and accelerated in a diode-type electro-optical system formed between the grid surface and an open anode plasma boundary. The anode plasma is produced in an electron beam transport channel through residual gas ionization by beam electrons and a plasma lens discharge. The plasma lens configuration of crossed electric and magnetic fields provides an attractive means to obtain a stable low-pressure plasma discharge. This geometry allows the compression of the electron beam in diameter from 6 to 1 cm with more than 100- ${\rm A}/{\rm cm}^{2}$ beam current density at the collector.

This is a brief review of last results of ongoing research of the new generation plasma optic devices on base of wide aperture cylindrical electrostatic plasma lens, that open up novel possibility for effective practical applications in modern high-tech. The most attractive new applications are removing microparticles from vacuum arc plasma stream as well as focusing large-area intensive electron beams of average energy.

An important disadvantage of the cathodic arc deposition is the presence in the plasma flow microdroplet fraction and their inclusion into the coating. The microdroplets adversely affect the performance of the coating and limiting the applications for cathodic arc deposition. First a new original approach for the effective removal of the microdroplets, as well as its conservation and incorporation into the plasma stream produced by erosion plasma sources (vacuum arc or laser produced plasma) has demonstrated in1. This approach is based on application of the cylindrical plasma lens (PL) configuration for introducing in a volume of propagating along axis dense low temperature plasma flow radially convergent energetic electron beam produced by ion-electron secondary emission from electrodes of plasma optical tool. Here we present the results of the further development an experimental study of new effective schemes eliminating microdroplets from plasma flow of the pulsed vacuum arc discharge (MEVVA). The main element of this scheme is a compact axially symmetric plasma-optic device based on the use of permanent magnets to establish the magnetic field. Actually the plasma lens is a well-explored tool for focusing high-current, large area, energetic, heavy ion beams as well as electron beams from gridded plasma sources2.

A joint research and development effort whose ultimate goal is to develop an intense, high charge state, ion source for mega-electron-volt ion implanters has been initiated. Present day high-energy ion implanters utilize low charge state (usually single charge) ion sources in combination with radio frequency (rf) accelerators. Usually, a MeV Linear Accelerator (MV LINAC) is used for acceleration of a few milliamperes. It is desirable to have instead an intense, high charge state ion source on a relatively low energy platform [direct current (dc) acceleration] to generate high-energy ion beams for implantation. This endeavor is a continuation of earlier research, which resulted in generating ions like Pb+7 and Bi+8 and ion currents exceeding 200 mA. The natural next step is to convert and optimize ion charge state enhancement techniques to generate B, P, As, and Sb ions, and adapt them to a dc implanter. A number of schemes are to be pursued simultaneously. The most promising approach is to be developed into a commercial ion source.

This paper is devoted to the engineering embodiment of the modern methods for producing charged ion and electron beams by extracting them from the plasma of a discharge. Electron beams use to execute electron-beam welding, annealing, and surface heating of materials and to realize plasmochemical reactions stimulated by fast electrons. Ion beams allow realization of technologies of ion implantation or ion-assisted deposition of coatings thereby opening new prospects for the creation of compounds and alloys by the method that makes it possible to obtain desired parameters and functional properties of the surface. A detailed description is given to the performance and design of devices producing beams of this type: the ion and electron sources being developed at the laboratory of plasma sources of the Institute of High-Current Electronics of the Russian Academy of Sciences and the laboratory of plasma electronics of Tomsk State University of Control Systems and Radioelectronics.

Conclusive demonstration of electron-beam enhancement of ion charge states for the Metal Vapor Vacuum Arc (MEVVA) ion source was recently achieved using an external electron beam (E-MEVVA) in experiments performed jointly among the Institute for Theoretical and Experimental Physics (ITEP), Moscow, Russia, the High Current Electronics Institute (HCEI), Tomsk, Russia, and Brookhaven National Laboratory (BNL), USA. The E-MEVVA experiments were performed in Moscow and Tomsk with nearly the same design of ion sources. Results for lead and bismuth cathodes yielded maximum ion charge states of Pb7+ and Bi8+ for E-MEVVA, as compared to Pb2+ and Bi2+ for conventional MEVVA operation. Additional encouraging results were also obtained using a Z-discharge to produce an internal electron-beam (Z-MEVVA and LIZ-MEV).

We report detailed investigations of the electron-beam metal vapor vacuum arc (E-MEVVA) ion source. The experiments were performed in Moscow and Tomsk with nearly the same design of ion sources. We recently reported the first conclusive demonstration of electron-beam enhancement of MEVVA performance using lead and bismuth cathodes, which yielded maximum ion charge states of Pb7+ and Bi8+ for E-MEVVA, as compared to Pb2+ and Bi2+ for conventional MEVVA operation. In this article we report extensive results for additional cathode materials, further details of the Moscow and Tomsk ion sources, and a discussion of electron beam effects on E-MEVVA performance. These results can be considered as a proof of the E-MEVVA principle.

We report detailed investigations of the electron-beam metal vapor vacuum-arc (E-MEVVA) ion source, which were performed jointly among the Institute for Theoretical and Experimental Physics, Moscow, Russia, the High Current Electronics Institute, Tomsk, Russia, and Brookhaven National Laboratory, USA. The experiments were performed in Moscow and Tomsk with nearly the same design of ion sources. Recently, the first successful ion charge states enhancement for this kind of ion source was demonstrated. This article presents comparisons of electron-beam effects and examines their influence on E-MEVVA performance. Substantial enhancement of high ion charge states enhancement was observed clearly in both experimental setups with two different methods of measuring the ion charge state distributions. These results can be considered as a proof of the E-MEVVA principle.

We describe our observations of the transport through an electrostatic plasma lens of a wide-aperture, high-current, low energy, metal-ion plasma flow produced by a cathodic arc discharge. The lens input aperture was 80 mm, the length of the lens was 140 mm, and there were three electrostatic ring electrodes located in a magnetic field formed by permanent magnets. The lens outer electrodes were grounded and the central electrode was biased up to −3 kV. The plasma was a copper plasma with directed (streaming) ion energy 20–40 eV, and the equivalent ion current was up to several amperes depending on the potential applied to the central lens electrode. We find that when the central lens electrode is electrically floating, the current density of the plasma flow at the lens focus increases by up to 40%–50%, a result that is in good agreement with a theoretical treatment based on plasma-optical principles of magnetic insulation of electrons and equipotentialization along magnetic field lines. When the central l...

Phosphorus is a much used dopant in semiconductor technology. Its vapors represent a rather stable tetratomic molecular compound and are produced from one of the most thermodynamically stable allotropic forms of phosphorus-red phosphorus. At vacuum heating temperatures ranging from 325 °C, red phosphorus evaporates solely as P4 molecules (P4/P2 ∼ 2 × 10(5), P4/P ∼ 10(21)). It is for this reason that red phosphorus is best suited as a source of polyatomic molecular ion beams. The paper reports on experimental research in the generation of polyatomic phosphorus ion beams with an alternative P vapor source for which a gaseous compound of phosphorus with hydrogen - phosphine - is used. The ion source is equipped with a specially designed dissociator in which phosphine heated to temperatures close to 700 °C decomposes into molecular hydrogen and phosphorus (P4) and then the reaction products are delivered through a vapor line to the discharge chamber. Experimental data are presented reflecting the influence of the discharge parameters and temperature of the dissociator heater on the mass-charge state of the ion beam.

This paper presents the results of a study on the generation of multiply charged ions in the plasma of a vacuum arc discharge. The average charge of ions in the plasma is increased by using a strong magnetic field, a current “burst,” or an accelerated electron beam. The results of measurements of the ion charge distribution for each case are reported.

Directed ion velocities in a vacuum arc discharge plasma are measured on the basis of a study of the ion emission current response to a rapid change of arc current. It is shown that these velocities are about 106 cm/s, are determined by the cathode material, and are almost independent of the ion charge number. Applying a magnetic field results in an increase in the directed ion velocity. As the gas pressure increases, the directed ion velocity decreases; this is the only case where the directed velocities are observed to depend on the ion charge number.

The TITAN source generates wide-aperture beams of gas and metal ions of different materials. This is achieved because of two types of cold-cathode arc discharges, which operate simultaneously in the discharge system of the source. For metal ions to be obtained, use is made of the vacuum arc initiated between an ion-forming cathode and a hollow anode. To produce gas ions, a constricted low-pressure arc discharge is initiated with the same hollow anode. The constitution of ion beams generated by the TITAN source has been investigated using a homemade time-of-flight spectrometer. This paper describes the design of the latter and the principle of its operation, and discusses the physical peculiarities of the spectrometer operation, which affect the ion beam constitution.

Based on time of flight method, influence of short time vacuum arc current jump on arc plasma parameters were investigated. Superposition of the current pulse of a vacuum arc with a high operating voltage results in the appearance of ions of higher charge state in the discharge plasma and in an increase in the mean ion charge state for most of the cathode materials used in the experiment. The method of a "short-time current jump" can be also used to investigate the parameters of a vacuum arc, in particular to estimate the ion direct velocities in vacuum arc plasmas. Our estimates show that in the presence of a current step the ion velocities are almost identical for all differently charged ions and depend only on the peak current and the ion mass.

Smaller semiconductors require shallow, low energy ion implantation, resulting space charge effects, which reduced beam currents and production rates. To increase production rates, molecular ions are used. Boron and phosphorous (or arsenic) implantation is needed for P-type and N-type semiconductors, respectively. Carborane, which is the most stable molecular boron ion leaves unacceptable carbon residue on extraction grids. A self-cleaning carborane acid compound (C4H12B10O4) was synthesized and utilized in the ITEP Bernas ion source resulting in large carborane ion output, without carbon residue. Pure gaseous processes are desired to enable rapid switch among ion species. Molecular phosphorous was generated by introducing phosphine in dissociators via 4PH3 = P4 + 6H2; generated molecular phosphorous in a pure gaseous process was then injected into the HCEI Calutron-Bernas ion source, from which P4(+) ion beams were extracted. Results from devices and some additional concepts are described.

The results of metal ion implantation into alumina ceramic are presented. We show that the of ceramic surface resistivity depends on the metal ion spcies used for the implantation, and decreases with increasing metal ion implantation dose, decreasing by 3–4 orders of magnitude from 1012 Ohm/sq. This approach provides an effective tool for bleeding off accumulated surface charge of ceramic components that can result from interaction with charged particles flows or dielectric polarization. The method can be applied for increasing the maximum electric field hold-off of insulating surfaces in high-voltage devices.

This paper presents research results on focusing and transport of an intense (up to 100 A) nonrelativistic (up to 20 kV) pulsed electron beam using a positive space charge plasma lens. The electron source is based on electron extraction from the plasma of a hollow-anode vacuum arc discharge. The arc is initiated by a dielectric surface flashover. The emission hole is covered with a fine mesh grid. The beam is extracted and accelerated in a diode-type electron-optical system formed between the grid surface and an open anode plasma boundary. The anode plasma is produced in an electron beam transport channel by residual gas ionization by beam electrons and the plasma lens discharge. The plasma lens configuration of crossed electric and magnetic fields provides an attractive means for obtaining a stable low-pressure plasma discharge. This geometry allows compression of the electron beam from 6 cm to 1 cm in diameter with more than 100 A/cm2 beam current density at the collector.

We report demonstrations of ion charge-state enhancement for an electron-beam metal-vapor vacuum-arc (E-MEVVA) ion source. Results with a lead cathode yielded a maximum ion charge state of Pb7+, which implies an ionization potential of at least 130 eV. Electron current densities j=70 A/cm2 and ionization times τ≅100 μs produced jτ=9.2×10−3 C/cm2 (5.8×1016 electrons/cm2). Standard analysis for these conditions indicates—somewhat surprisingly—that successive single (stepwise) ionization accounts for the present observations, even though the charge states are substantially higher than most previous results with MEVVA-based ion sources.

This paper presents the results of experimental studies of a new design of discharge system using a self-heated hollow cathode. The discharge system offers certain advantages that are attractive for use in high-dose ion implantation, plasma generators, and plasma electron sources.