We report our investigations on a planar (o 125 mm) high-current (up to 50 A) pulsed (100-400 mu s) magnetron discharge with injection and acceleration of auxiliary electrons into the cathode layer. The injected electrons were from the plasma of a pulsed (300 mu s) vacuum-arc discharge with current amplitude 10-60 A. The magnetron targets were Cu and Zn, and the operating gas was argon. The use of a gasless vacuum-arc electron emitter leads to further decrease in the minimum operating pressure of the high-current form of magnetron discharge, down to 0.18 mTorr (0.024 Pa). We present here the experimental results and a numerical model of the evolution of the ion mass-to-charge composition of the magnetron plasma as the operating pressure decrease to its ultimate lower limit.

Pure boron coatings have been deposited on stainless-steel substrates using a planar magnetron with a thermally insulated target of pure crystalline boron in a direct current discharge of up to 50 mA in an argon atmosphere. The magnetron was designed to be used as a component in an electron-ion-plasma test bench for in situ monitoring of boron deposition growth using synchrotron radiation from the VEPP-3 electron storage ring at the Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences. Using this magnetron, we have fabricated boron films with thickness up to 1.5 μm and studied their surface morphology, mechanical properties, and coating composition.

The features of the probe technique are described and the results of measuring the parameters of plasma generated by a planar magnetron sputtering system with a pure boron target during coating deposition are presented. A feature of probe measurements was the use of heating the collecting surface of a single Langmuir probe. Heating led to a decrease in the electrical resistance of the boron film on the surface, which made it possible to carry out in situ probe measurements of the magnetron discharge plasma parameters during the entire process of boron coating. Keywords: plasma parameters, probe method, planar magnetron, boron films.

Представлен сравнительный анализ процессов функционирования и нанесения покрытий вакуумным и газовым магнетроном в частотно-импульсном режиме самораспыления с медной и серебряной мишенями.Осо бенностью проведенных исследований является использование единого устройства, функционирующего при различных давлениях аргона: 2 10-3 Торр и 10-5 Торр.Сравнение характеристик устройства при таких давлени ях и свойств полученных покрытий на поверхности образцов показало

In this study, boron thin films were deposited on metal substrates using planar direct current (DC) magnetron sputtering with a pure boron target. Boron has high electrical resistance, severely impeding its application in a magnetron discharge; however, it is a semiconductor and its resistance decreases as the temperature increases. We used a planar magnetron with a boron target that was heated in a DC discharge current up to 50 mA in argon and nitrogen at a pressure of 2-3 mTorr. For these discharge parameters, at a distance of 5 cm from the target the boron deposition rate was about 150 nm/h. Thin boron films with thickness up to 1 μm were obtained and their surface morphology was studied. The deposition technique and the properties of the films are discussed.

Planar magnetrons with a heated crystalline boron target are promising for depositing boron coatings intended for a wide range of scientific and industrial applications. The promotion of this type of magnetrons requires an in-depth investigation of the coating deposition process. A new version of such a magnetron is created for the vacuum electron-ion-plasma (VEIP) test installation for in situ synchrotron radiation monitoring of the boron coating synthesis. The paper proposes the design and parameters for this magnetron and discusses the boron coating deposition using the VEIP test installation.

The features of the probe technique are described and the results of measuring the parameters of plasma generated by a planar magnetron sputtering system with a pure boron target during coating deposition are presented. A feature of probe measurements was the use of heating the collecting surface of a single Langmuir probe. Heating led to a decrease in the electrical resistance of the boron film on the surface, which made it possible to carry out in situ probe measurements of the magnetron discharge plasma parameters during the entire process of boron coating.

We describe the use of a modified residual gas analyzer based on a quadrupole mass spectrometer to measure the ion mass-to-charge composition of the plasma of a repetitively pulsed planar magnetron discharge. The pulse duration and frequency parameters necessary to ensure reliable plasma ion composition data are determined. Examples of measurements of the ion mass-to-charge spectra are given.

Deposition of boron-containing coatings is determined by their promising use for surface modification goals. In this work, we consider the equipment for the implementation of two plasma methods for the deposition of thin films of pure boron on the surface. These are a magnetron sputtering with a crystalline boron target heated in the discharge, and a system of an evaporation of pure boron target by an electron beam generated using forevacuum plasma source. The features of functioning, and operating parameters of these devices are presented. The deposition rate of boron coatings on the samples was about 20 nm/min for magnetron sputtering. The boron film deposition rate was significantly higher and reached 1 µm / min.

The design, the principle of operation, and the characteristics of a planar magnetron sputter for pure boron coatings are presented. A feature of this device is the use of a thermally insulated target (cathode) made from pure crystalline boron, which is heated by an auxiliary low-current discharge to provide an electrical conductivity sufficient for the stable functioning of the magnetron discharge. This makes it possible to realize a DC mode and a pulsed self-sputtering mode in the magnetron, where boron ions in the discharge plasma dominate over the working gas ions. Another feature of the magnetron is the use of a slotted anode of a special design, which ensures stable and long-term operation of the device when a non-conductive boron film is applied to the anode surface. When using a pulsed discharge with a peak current of 40 A, a pulse duration of 400 μs, and a pulse repetition rate of 25 pps, the deposition rate of pure boron coatings on a substrate installed at a distance of 10 cm from the cathode is comparable with the deposition rate of the coatings in a DC magnetron discharge with a current of 300 mA and is found to be about 20−30 nm/min.

We describe our investigations of a plasma-cathode electron source designed for the deposition of oxide coatings by the electron-beam evaporation of dielectric materials. Tests carried out using oxygen as the working gas showed that the source is operable without a change in parameters for at least ten hours of continuous operation. The current–voltage characteristics of the hollow-cathode plasma source in oxygen displayed a monotonically increasing character, and the voltage dependence of the discharge current was exponential. At the same time, for argon, nitrogen, and helium, the discharge voltage remained unchanged over a current ranging from 0.1 A to 1 A. A possible reason for these differences is the formation of oxides on the electrode surfaces for operation in the oxygen, impeding the discharge operation and requiring higher voltages for the same current as the other gases. The dependencies of the electron beam current on the accelerating voltage were monotonically increasing curves for all the gases except for helium, for which the beam current remained unchanged with increasing voltage over a range from two to ten kilovolts.

In an ion source based on a pulsed planar magnetron sputtering discharge with gas (argon) feed, the fraction of metal ions in the ion beam decreases with decreasing gas pressure, down to the minimum possible working pressure of the magnetron sputtering discharge. The use of a supplementary vacuum arc plasma injector provides stable operation of the pulsed magnetron sputtering discharge at extremely low pressure and without gas feed. Under these conditions, the pressure dependence of the gaseous ion fraction displays a maximum (is nonmonotonic).

The mass-to-charge ion composition of a planar magnetron discharge plasma has been investigated. The measurements used a modified quadrupole mass-spectrometer and a time-of-flight spectrometer. The experiments were carried out on a copper magnetron target. Argon was used as a working gas. The operating pressure was 0.15÷1.3 Pa. The discharge current was 1÷20 A with a pulse duration of 30÷50 μs. The influence of main operating parameters (discharge current and working gas pressure) on mass-to-charge composition of plasma ions was measured. The mass-to-charge composition of plasma ions in the axial direction was measured as a function of working pressure. Plasma electron temperature was measured and its effect on the mass-to-charge composition of magnetron plasma ions was estimated.

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 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 10 B + and 11 B + boron isotope ions with doses of 10 14 –10 16 ion/cm 2 , 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.

We have designed, fabricated and characterized an ion source based on a vacuum magnetron discharge. The magnetron discharge is initiated by a vacuum arc discharge, the plasma of which flows onto the magnetron sputtering target working surface. The vacuum arc material is usually the same as that of the magnetron target. The discharges operate at a residual pressure of 3 × 10−6 Torr without working gas feed. Pulses of vacuum arc (30 μs) and magnetron discharge (up to 300 μs) are applied simultaneously. After ignition by the vacuum arc, the magnetron discharge runs in a self-sustained mode. Cu–Cu, Ag–Ag, Zn–Zn, and Pb–Pb pairs of magnetron target material and vacuum arc cathode material were tested, as well as mixed pairs; for example, Cu vacuum arc cathode and Pb magnetron target. An ion beam was extracted from the discharge plasma by applying an accelerating voltage of up to 20 kV between the plasma expander and grounded electrodes. The ion beam collector current reached 80 mA. The ion beam composition, analyzed by a time-of-flight spectrometer, shows that the beam consists mainly of singly-charged (about 90%) and doubly-charged (about 10% current fraction) magnetron target material ions. The ion beam radial current density non-uniformity was as low as ±5% over a diameter of 6.6 cm, which is the diameter of the source output aperture.

We have investigated the supersonic flow of dense plasma, formed by a pulsed vacuum arc, in a magnetic field of about 1 T using probe and optical diagnostics. Two separate magnetic field configurations were examined—an axial field with either converging or diverging lines of force. We find that for a low-current arc of from 0.4 to 1 kA and pulse duration of 270 $\mu \text{s}$ , the diverging magnetic field leads to increased plasma flow velocity by about a factor of 2.5, whereas the converging magnetic field reduces the velocity by about the same amount. For a high-current arc of from 5 to 30 kA and pulse duration of $40~\mu \text{s}$ , the plasma flow velocity increases, although the effect of increased field strength on flow velocity is less significant. Here, we describe these observations and other effects of magnetic field on the parameters of the vacuum arc plasma flow.

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 x 10(-4) - 2 x 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 have developed a vacuum (gasless) magnetron discharge initiated by a vacuum arc plasma. The discharge operating conditions for different magnetron target materials have been determined. The mass-to-charge plasma composition and its evolution during a discharge current pulse were measured. It is shown that, after transient processes of cathode outgassing and purification, the plasma ion component consists mainly of singly-charged ions of the magnetron target material. The measured total ion current from the vacuum magnetron discharge plasma is up to 7.5% of the discharge current.

The effect of operating pressure in the ultra-low range (down to 7 x 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.