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A nanorelief forming on a copper surface under oblique irradiation with cluster ions has been examined at different irradiation doses and target temperatures. This nanorelief has been found to evolve into an ordered undulating structure. It has been demonstrated that the initial roughness is smoothed out at higher target temperatures. The mechanisms of formation of the surface topography have been identified, and their efficiency has been determined.

This article presents the results of gold deposition into pores of SiO $${}_{2}$$ /Si matrices and the modifications of the obtained SiO $${}_{2}$$ (Au)/Si systems by irradiation with argon Ar $${}^{+}$$ ions with an energy of 100 keV with a fluence of $$5\times 10^{14}$$ ion/cm $${}^{2}$$ . The effect of irradiation on changes in the surface topography of SiO $${}_{2}$$ (Au)/Si systems and the signal intensity of surface-enhanced Raman scattering during the detection of the model analyte (methylene blue) have been shown.

A study was made of the dependence of the contrast value of a negative electron resist based on hydrogen-silsesquioxane (HSQ) in the process of the development of NaOH–NaCl in an aqueous alkaline-salt solution at various temperatures. When the temperature of the developer rises from 22 to 40°C the contrast increases by 45%. An increase in contrast was also found with a decrease in the developing temperature by 27% to 10°C compared with the developing temperature of 22°C. Thus, a nonmonotonic change in the contrast of the HSQ resist from the temperature of the development was established. Studies of AFM images of test structures in areas where exposure to the HSQ resist was performed demonstrate the phase contrast even in regions with zero resist thickness after development, which indicates a change in the adhesive properties of the surface.

We have studied a new approach to the analysis of carbon-containing materials by secondary ion mass spectrometry (SIMS), which allows determining the contents of carbon atoms in sp2 and sp3 hybridization states. According to this, the main SIMS parameter characterizing the atomic concentration N(sp3) is defined as the intensity ratio of C8/C7 secondary cluster ion peaks. Based on the results of SIMS analysis of several test compositions, a calibration dependence of N(sp3) versus C8/C7 peak intensity ratio has been obtained. The depth profiles of N(sp3) for diamond-like carbon (DLC) grown on diamond and silicon substrates were obtained, which showed (i) N(sp3) variation from 0.3 to 0.6 depending on the DLC growth regime and (ii) inhomogeneous distribution of N(sp3) in depth of the samples.

Gas cluster ion beam is known as a tool for surface smoothing; at the same time, surface relief formation under oblique beam incidence was reported. We suggested using samples with pre-formed surface pattern to study its evolution caused by ion irradiation and applied this approach to reveal the mechanisms responsible for nanorelief developing under off-normal cluster ion incidence. The role of key processes, which are ballistic diffusion and sputtering depending on the local incidence angle and surface curvature, is discussed. The irradiation conditions as well as the initial patters found to influence on the resulting surface shape.

We have developed a solid electrolyte ion source (SEIS) with CsAg4Br2.68I2.32 film deposited on a silver tip. In the paper, Ag+ ion emission was significantly enhanced and the ion current of 1.6 μA was obtained at 168 °C temperature and 20 kV accelerating voltage. I-T and I-U characteristics were well described by the field evaporation (FEV) model, and the surface potential barrier was estimated to be 0.19 eV. Experimental investigations of the Ag+ ion emission mechanisms revealed that the solid electrolyte film plays an important role of ion-transport system, and the emitted Ag+ ions were compensated by the ions diffusing from the silver reservoir (Ag-tip). The developed SEIS was exploited for the synthesis of Ag nanoparticles on Si surface. The average size of these nanoparticles was estimated 15.5 ± 0.3 nm, and the projected range Rp of the low-energy high-dose Ag+ ions implanted Si sample was found to be less than 5 nm using TOF-SIMS depth profiling. The future application of SEISs in ion propulsion systems of miniature spacecraft with limited on-board payloads was discussed, and the thrust was estimated within μN range.

Rationale Continuously downscaling integrated circuit devices requires fabrication of shallower p-n junctions. The ion implantation approach at low energy is subject to low beam current due to the Coulomb repulsion. To overcome this problem cluster ions can be used for implantation. In comparison with single ions, cluster ions possess lower energy per atom and reduced Coulomb repulsion resulting in high equivalent current. Methods In this study to carry out low-energy implantation into single crystalline silicon and 4H-SiC samples we employ Aln - (n = 1-5) clusters with energy in the range of 5-20 keV. The Al clusters are obtained by Cs sputtering of Al rod. Time-of-flight secondary ion mass spectrometry (TOF-SIMS; IONTOF TOF.SIMS-5) is used to study aluminum and oxygen sputter depth profiles for different cluster sizes and implantation energies before and after annealing treatment. Results A distinguishable effect of the energy per atom in the cluster on reduction of the projected range Rp is revealed. The lowest Rp of 3 ± 1 nm has been achieved in SiC samples at the energy per atom of 1.66 keV. After annealing of Si samples, a considerable change in the Al profiles due to redistribution of Al atoms during motion of the front of recrystallization is observed. The influence of the number of atoms in the cluster at the same energy per atom within the experimental uncertainty is not observed. Conclusions The transient effects of the sputtering by the primary ion beam distort the shape of the Al profiles in Si samples. In the case of SiC, due to its relatively lower surface chemical activity, more informative TOF-SIMS depth profiling of the shallow cluster implantation is feasible.

In this paper, we study time-of-flight (TOF) mass-spectra of the Ar cluster beams obtained by nozzles with different diameters, at different source pressures, and ionizing electron energies. The TOF mass-spectra are measured at minimal electron energy, since there is a strong influence on the mass-spectra by the multiple ionization of the clusters. The cluster size derived from TOF mass-spectra is considered as a function of the condensation parameter Γ*. Attenuation of the cluster current due to collisions with residual gas is also studied. An estimation of the relative cluster size by the current attenuation is proposed.

Transonic and supersonic flows near the cones were visualized with two types of discharges. Pulse volume discharge with pre-ionization by plasma sheets was used to visualize the flow with discontinuities with time resolution in nanosecond range. Bow shock angle was measured by the glow images, and flow Mach number calculated. Stationary discharge was used to record a non-changing weakly luminous micro-nozzle jet flow spreading into a high vacuum region and interacting with a conical metal skimmer, which is essential for gas cluster equipment. A fusiform Mach barrel at the nozzle exit and the bow shock at the obstacle are visualized. The computational flow dynamics model based on Navier–Stokes–Fourier equations was verified by comparison with the experimental images and showed a good agreement with the observed flow structure.

A custom-built gas cluster ion source with an energy up to 20 keV is constructed. Ar, CO2, N2, and O2 are used as the working gases. The clusters are formed by metal conical nozzles with critical diameters of 65−135 um and a cone angle of 14°. To facilitate evacuation of the chambers we use the pulse mode of nozzle feeding. This allows an increase in the gas pressure in the stagnation zone (inlet pressure) up to 15 bar. The current of the clusters with an energy of 20 keV is 20 µA; the maximal current density is 3 µA/cm2. The mass spectra of the argon clusters formed at different pressures and electron ionization energy are studied by time-of-flight spectroscopy. The inlet pressure dependence of the mean cluster size is considered as a function of the condensation parameter Г*. An argon cluster beam is used to smooth the surface of the titanium coating and pressed silicon nanopowder. The roughness of the Ti coating surface decreases from 3.7 to 0.8 nm; the removal of microparticles from the surface is also observed. In the case of the surface of Si, besides the smoothing effect the formation of 100 nm craters is observed.

Results of investigation of the mass spectra of secondary ions sputtered from bulk (continuous) and porous silicon targets with various characteristic core particle dimensions are presented. It has been established that the sputtering of nanostructured Si samples leads to a significant increase in the relative yield of massive cluster ions. This effect is especially pronounced when the characteristic nanoparticle size approaches the range of bombarding ions in the Si target. The obtained results are explained taking into account the confinement of atomic collision cascades.

This paper proposes the use of surfaces with a preformed ordered nanotopography to study the mechanisms of the evolution of surface topography under ion beam irradiation. The proposed approach is used for silicon surface bombardment with an oblique beam of accelerated cluster ions. Samples with an ordered topography were formed using electron lithography. The surface was studied using the SEM and AFM techniques. It is shown that the resulting topography is formed as a result of the competition between processes of sputtering and redistribution of atoms. The effectiveness of these processes is determined by the local incidence angles of the ions and the surface curvature. The possibility of obtaining an asymmetric surface profile with the specified parameters is shown by selecting the incidence angle of the ion beam, the irradiation dose, and the initial surface topography.

Electrochemical etching of Si is a promising method of fabricating multilayer photonic structures with hundreds of layers. Nevertheless, the natural cleavage of the porous silicon structure has roughness and then high optical scattering that embarrasses the usage of porous silicon in optical devices. In this study, gas cluster ion beam irradiation was suggested as a polishing technique. The bombardment results in surface smoothing and consequent enhancement of light reflection without significant difference in sputtering rate of layers with different porosity. Increasing irradiation dose results in different behavior of porous layers: densification of low-porosity structures and nano-rods formation in high-porosity layers.

The results of ab initio studies of the atomic and charge structure of small clusters and cluster ions formed by 13 and 19 argon atoms are reported. It was found that the icosahedral atomic structure is energetically the most favorable for such clusters. The calculations demonstrate that when a single electron is removed from a cluster, the excess positive charge is distributed primarily over the surface of the formed cluster ion.

An influence of the specific kinetic energy Esp and nuclearity n of Bin+ (n = 1–4) projectiles on the sputter yield of Si was studied by means of the volume loss method. It was found that the specific sputter yield Ysp exhibited non-additive increase with an increasing of n and Esp values. As a non-additivity k-factor, the slope of the straight line approximating Ysp(n) dependences at the same specific energy was proposed to use. For Bin+ (n = 1–4) projectiles at Esp = 10 keV at−1 the k-factor was equal to 0.41 ± 0.08. In addition, it was ascertained that the efficiency of energy transfer from projectiles to target atoms increased with an increase in the projectile nuclearity, e.g., it was 2.8 times greater for Bi3+ bombarding ions as compared with Bi+ ones.

We present experimental studies and computer simulations of the energy distributions of the particles sputtered from copper and molybdenum with gas cluster ions. Both experimental and simulated distributions were found to be narrower than ones known for atomic ion sputtering. It was shown that the distributions of sputtered atoms obtained by molecular dynamics simulations can be well described in frames of the thermal spike theory. For a given cluster energy, its size and the target material properties determine the parameters of the distributions. Including into consideration sequential cluster impacts on the target surface resulted in changes both in energy and angular distributions of sputtered matter and as well in total sputtering yield. Experimentally measured distributions well matched the ones simulated in “sequential” mode.

Polycrystalline NiPd and Ni5Pd alloys were irradiated with argon gas cluster ion beam and atomic ion beam. In situ XPS measurements showed surface enrichment with Ni. For cluster ions, the degree of the enrichment was significantly higher, and the ion current density influenced on it. Under oblique cluster ion beam, ripples developed on the surface, and the elements of the alloy redistributed along the surface according to the ripple pattern. For normal cluster ion beam direction, sputtering rate was determined by a crystalline orientation, which limited the smoothing effect.

The temperature dependence of the ripples formation on a copper surface under off-normal gas cluster ion beam irradiation was investigated. At room temperature, well developed asymmetric ripples perpendicular to the beam were obtained with “droplets” of copper at the crests. At elevated temperatures, surface smoothing was found instead of rippling. On some grains the ripples perpendicular to the ion beam still remained. To explain this fact, electron backscattered diffraction analysis of the samples surfaces was performed. It showed that the ripple formation at elevated temperatures is governed both by the ion beam direction and by the crystalline orientation of a grain with respect to the beam.

The experimental angular distributions of atoms sputtered from polycrystalline W and Cu with 10 keV Ar and Xe cluster ions are presented. RBS was used to analyze a material deposited on a collector. It has been found that the mechanism of sputtering, connected with elastic properties of materials, has a significant influence on the angular distributions of sputtered components. The angular distributions were simulated using molecular dynamics calculations. A new approach taking into account experimental cluster mass distributions in the beam and surface topography was developed. This approach was fruitful for understanding the particular features of the experimental angular distributions of sputtered material.

Defect formation in silicon-on-sapphire films under the action of a gas beam of 30 keV argon cluster ions is studied. Rutherford backscattering in the channeling mode is used to demonstrate the formation of a large number of defects in the volume of a specimen that is irradiated by a cluster ion beam without mass separation. If atomic and light cluster ions are removed from the beam, defect-free etching of the specimen occurs.

We have studied the influence of bombardment with accelerated gas-cluster ions on the surface topography of silicon carbide and diamond. Atomic-force microscopy shows that exposure to 10-keV gas-cluster ions at a total dose above 1016 cm–2 leads to smoothing of the surface relief. The ion-etching rate and efficiency of the surface relief smoothing as dependent on the thickness of removed layer have been estimated. Raman-spectroscopy data show that surface irradiation with gas-cluster ions does not introduce defects into the crystalline structure of irradiated material.