Sputtering of pure boron using a magnetron without a radio-frequency supply

Boron at room temperature is insulating and therefore conventionally sputtered using radio-frequency power supplies including their power-matching networks. In this contribution, we show that through a suitable ignition assistance, via temporary application of a high voltage (∼600 V) to the substrate holder or auxiliary electrode, the magnetron discharge can be ignited using a conventional mid-frequency power supply without matching network. Once the discharge is ignited, the assisting voltage can be reduced to less than 50 V, and after the boron target surface is at elevated temperature, thereby exhibiting sufficient conductivity, the assisting voltage can be turned off. The deposition of boron and boron nitride films has been demonstrated with a deposition rate of approximately 400 nm/h for a power of 250 W

Electron-Beam Synthesis and Modification and Properties of Boron Coatings on Alloy Surfaces

In this study, fore-vacuum plasma electron beam sources were used to deposit a few micron-thick boron coatings on A284 and ZrNb1 alloys and modify their surfaces. The coating deposition rate with a continuous 1 kW electron beam that evaporated the boron target at a distance of 10 cm was 0.5 µm/min, and the boron coating density was 2.2 g/cm3. Based on the comparison of data on the mass-to-charge composition, beam plasma density, and coating parameters, the contribution of the plasma phase of the evaporated material to the growth of coatings was greater than that of the vapor phase. Using the scanning electron and atomic force microscopy techniques, surface modification by repeated electron beam pulses with electron energies of 8 and 6 keV and a beam power per pulse of 2 J/cm2 and 2.25 J/cm2, respectively, transformed a relatively smooth coating surface into a hilly structure. Based on a structural phase analysis of coatings using synchrotron radiation, it was concluded that the formation of the hilly coating structure was due to surface melting under the repeated action of electron beam pulses. The microhardness, adhesion, and wear resistance of coatings were measured, and their corrosion tests are presented herein. The pure boron coatings obtained and studied are expected to be of use in various applications

Electron-Beam Synthesis and Modification and Properties of Boron Coatings on Alloy Surfaces

In this study, fore-vacuum plasma electron beam sources were used to deposit a few micron-thick boron coatings on A284 and ZrNb1 alloys and modify their surfaces. The coating deposition rate with a continuous 1 kW electron beam that evaporated the boron target at a distance of 10 cm was 0.5 µm/min, and the boron coating density was 2.2 g/cm3. Based on the comparison of data on the mass-to-charge composition, beam plasma density, and coating parameters, the contribution of the plasma phase of the evaporated material to the growth of coatings was greater than that of the vapor phase. Using the scanning electron and atomic force microscopy techniques, surface modification by repeated electron beam pulses with electron energies of 8 and 6 keV and a beam power per pulse of 2 J/cm2 and 2.25 J/cm2, respectively, transformed a relatively smooth coating surface into a hilly structure. Based on a structural phase analysis of coatings using synchrotron radiation, it was concluded that the formation of the hilly coating structure was due to surface melting under the repeated action of electron beam pulses. The microhardness, adhesion, and wear resistance of coatings were measured, and their corrosion tests are presented herein. The pure boron coatings obtained and studied are expected to be of use in various applications

Electron-Beam Synthesis of Dielectric Coatings Using Forevacuum Plasma Electron Sources (Review)

This is a review of current developments in the field of ion-plasma and beam methods of synthesis of protective and functional dielectric coatings. We give rationales for attractiveness and prospects of creating such coatings by electron-beam heating and following evaporation of dielectric targets. Forevacuum plasma electron sources, operating at elevated pressure values from units to hundreds of pascals, make it possible to exert the direct action of an electron beam on low-conductive materials. Electron-beam evaporation of aluminum oxide, boron, and silicon carbide targets is used to exemplify the particular features of electron-beam synthesis of such coatings and their parameters and characteristics

Dielectric Coating Deposition Regimes during Electron-Beam Evaporation of Ceramics in the Fore-Vacuum Pressure Range

We present experimental results on the deposition of dielectric coatings on metal surfaces by electron-beam evaporation of alumina ceramics in nitrogen and oxygen gas medium at the pressures of 5–30 Pa. The feasibility of implementing this approach is associated with the use of unique fore-vacuum plasma electron sources. The effect of electron beam power on the rates of ceramic target evaporation and, consequently, on the coating deposition rate is investigated. The structure, electrical-insulating and mechanical (wear resistance, adhesion) properties of the deposited coatings is investigated. We also show the possibility of using coatings for electrical insulating of wires and monolithic integrated circuits

Ion Composition of the Beam Plasma Generated by Electron-Beam Evaporation of Metals and Ceramic in the Forevacuum Range of Pressure

We present the results of measurements of the ion composition of the plasma generated by an accelerated electron beam in the forevacuum pressure range. It has been found that the main contribution to ionization processes comes from beam electrons. It has been shown that, during the electron-beam evaporation of metal or ceramic targets, the number of ions evaporated from the materials in the beam plasma significantly exceeds the number of ions produced from the residual atmosphere and admitted gases. Together, electron beams and beam-produced plasma can catalyze the processes of coatings deposition or modification of the surface layer of the samples