Denis O. Sivin

Formation of intermetallic layers at high intensity ion implantation

The experimental results are presented on a study of intermetallic phase formation in the surface zone of metal target at high intensity ion implantation. High intensity ion implantation allow to obtain the surface-alloyed layers of a much greater thickness in comparison with ‘ordinary’ ion implantation. Pure polycrystalline nickel was chosen as the target. The nickel samples were irradiated with the aluminum ions using the vacuum-arc ion beam and plasma flow source ‘Raduga-5’. The RBS and TEM were used for the investigations presented. It was established that the fine dispersed intermetallic precipitates are formed in the surface alloyed nickel layer. The alloyed layer thickness is equal to 150 nm and more, while the ion projected range that is equal to 70 nm. Compositions of these intermetallic precipitates are close to Ni3Al and NiAl phases. The solid solution of aluminum in nickel is also formed. The depth dependence of the formation of intermetallic phases can be deduced from the Ni–Al phase diagram.

Behavior of macroparticles near and on a substrate immersed in a vacuum arc plasma at negative high-frequency short-pulsed biasing

It was found that the negative repetitive pulsed biasing of a substrate with respect to the adjacent plasma significantly reduce the macroparticles (MPs) content on surface. The decrease of MPs on the negative potential substrate surface is caused by several different physical mechanisms. Up to 10% of macroparticles can be repulsed from the plasma-substrate voltage drop after being negatively charged in plasma. The MPs surface density on substrate can be significantly reduced after MPs interaction with negatively biased metal surface. This physical mechanism of negatively charged MPs electrostatic repulsion disappears when tungsten grid is used to create a sheath near the substrate surface. Reduction of MPs surface density almost by half takes a place due to ion sputtering. The decrease of MPs surface density by factor of 12 was achieved after the treatment of substrate for 2 min.

Plasma immersion ion charge state and mass spectrometer.

Investigation results of charge state of monocomponent plasma of Ti, Zr, W, and N, as well as that of multicomponent metal plasma of Ti/Zr (50/50 at.%) using plasma-immersion time-of-flight spectrometer are presented in the paper. The case of pressure impact in the working chamber on the ion charge state of combined metal (Ti) and gas-discharge (N) plasma is considered.

High-current vacuum-arc ion and plasma source "Raduga-5" application to intermetallic phase formation

Phase composition, structural state, and mechanical properties of the ion-doped surface layers of Ni, Ti, and Fe targets with Al and Ti ions implanted into using the metal ion beam and plasma source Raduga 5 have been investigated. The high-intensity mode of implantation allowed us to obtain the ion-doped layers with the thickness exceeding the ion projected range by several orders of magnitude. By the transmission electron microscopy, it has been found that the fine-dispersed equilibrium intermetallic phases (Me3Al, MeAl) and the solid solution of aluminum were formed in the doped Ni, Ti, and Fe surface layers at the depth of up to 2600nm. The maximum dopant concentration reached 75%. It has been shown that the average size of the formed phases was of 70nm. The microhardness of the different target surface layers increased by 1.5–3 times. The wear resistance of the samples did not change within the temperature range of 300–700K.

Unfiltered Aluminium Vacuum Arc Plasma Application for High-Frequency Short-Pulse Plasma Immersion Ion Implantation

This paper is devoted to the studying of the dynamical changes in the density of aluminium microparticles (MPs) on the substrate surface made of stainless steel, immersed in vacuum arc plasma, at high-frequency short-pulse negative bias potential. It is shown experimentally that the density of aluminium MPs on the substrate surface is decreased dynamically by 3 orders when the treatment time is increased from 15 s to 3 min at the bias potential –2 kV. A possibility of the application of MPs unfiltered vacuum arc plasma for high-frequency short-pulse plasma immersion ion implantation to form the intermetallic layers is discussed.

Mechanisms and regularities of the vacuum arc macroparticles behavior near and on a substrate, immersed in plasma

It was found that the negative repetitive pulsed biasing of a substrate with respect to the adjacent plasma significantly reduce the MPs content on surface. The decrease of MPs on the negative potential substrate surface is caused by several different physical mechanisms. Up to 10% of macroparticles (MPs) can be repulsed from the plasma-substrate voltage drop after being negatively charged in plasma. The MPs surface density on substrate can be significantly reduced after MPs interaction with negatively biased metal surface. This physical mechanism of negatively charged MPs electrostatic repulsion disappears when tungsten grid is used to create a sheath near the substrate surface. Reduction of MPs surface density almost by half takes a place due to ion sputtering. The decrease of MPs surface density by factor of 12 was achieved after the treatment of substrate for 2 min.

Pseudo ribbon metal ion beam source.

The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface.

Influence of Bias Parameters and Plasma Density on Vacuum Arc Macroparticle Accumulation

Several regularities of the accumulation of vacuum arc metal macroparticles (MP) on the sample on repetitively pulsed biasing (105 Hz, 7 µs, −0.5 kV to −3.5 kV) have been investigated. It has been shown that the substrate temperature plays a very important role in controlling the MP amounts on the sample. A possibility to change the metal particle number density on the substrate in the range from 105/cm2 to 107/cm2, depending on bias pulse parameters, sample temperature, and ion plasma saturation current density, has been demonstrated. The shape of MPs and their adhesion to the substrate surface depends strongly on the MP energy balance in a high-voltage space charge sheath.

Very Broad Metal Ion Beam Source for Ion Implantation and Coating Deposition Technologies

The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc driven vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 Gs on the cathode surface.

Mechanisms and behavioral regularities of the vacuum-arc microparticles near and on a potential electrode immersed in plasma

It is experimentally revealed that the pulse-periodic bias potential provides a multifold decrease in the surface content of microparticles (MPs). It is ascertained that a decrease in the MP concentration at the target can be explained by several physical mechanisms. From experiments with a fine-structure grid, it is found that less than 10% of MPs negatively charged in the plasma can be reflected in the electric field of the charge-separation layer near the sample. A substantial decrease in the MP density occurs after direct interaction between a MP and the sample under the action of a negative HF short-pulse bias potential. Almost half the MP surface density is caused by ion sputtering. A twelvefold reduction in the MP surface density is attained when the target is irradiated for 2 min.