A. A. Shemukhin

Layer-by-layer composition and structure of silicon subjected to combined gallium and nitrogen ion implantation for the ion synthesis of gallium nitride

The composition and structure of silicon surface layers subjected to combined gallium and nitrogen ion implantation with subsequent annealing have been studied by the X-ray photoelectron spectroscopy, Rutherford backscattering, electron spin resonance, Raman spectroscopy, and transmission electron microscopy techniques. A slight redistribution of the implanted atoms before annealing and their substantial migration towards the surface during annealing depending on the sequence of implantations are observed. It is found that about 2% of atoms of the implanted layer are replaced with gallium bonded to nitrogen; however, it is impossible to detect the gallium-nitride phase. At the same time, gallium-enriched inclusions containing ∼25 at % of gallium are detected as candidates for the further synthesis of gallium-nitride inclusions.

The Influence of the Gas Cluster Ion Beam Composition on Defect Formation in Targets

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.

Defect formation and recrystallization mechanisms in silicon-on-sapphire films under ion irradiation

The effect of the parameters (energy, dose) of the irradiation of silicon-on-sapphire (SOS) structures with ions Si+ ions on the quality of the silicon-film crystal structure after solid-phase epitaxial recrystallization and annealing is studied. It is shown that the most efficient mechanism of crystal-structure recovery is recrystallization from the silicon surface layer which is a seed.

Influence of ion-irradiation parameters on defect formation in silicon films

It is shown that unlike bulk silicon, for which amorphization is observed at an irradiation dose of 5 × 1016 ion/cm2, thin silicon films on sapphire are amorphized at lower critical doses (1015 ion/cm2). An undamaged surface layer remains when the silicon films are irradiated with Si+ ion beams. Its thickness depends on the current density of the incident beam. Rutherford backscattering studies show that annealing at 950°C improves the crystallinity of the irradiated silicon film. Annealing of the films at 1100°C leads to mixing of the silicon-sapphire interface.

Nuclear-physical analysis of the contamination on the surface of a COMPLAST panel after 12-year exposure at the ISS

Using methods of X-ray fluorescence analysis (XRFA), the Rutherford backscattering of ions (RBS) and spectral X-ray microanalysis (SXRM) in combination with scanning electron microscopy (SEM), we study the elemental composition and structure of contaminants on the surface of a metallic panel with samples of different materials exposed to outer space for 12 years. It turns out that the main elements of the contaminants are C, O, Si, S, Ca, Fe, and Zn. Since these elements are the constituents of materials located on the panel, they are present as a result of destruction of the materials under the action of outer-space factors. X-ray phase analysis (XRPA) of the contaminants shows that carbon is present in the form of an amorphous graphite phase with a small addition of crystalline graphite, while the other components are in an amorphous state. Crystalline silicium dioxide and other silicium compounds are not found.

Study of silicon implanted with zinc and oxygen ions via Rutherford backscattering spectroscopy

The structural features and dopant profiles of a Si surface layer implanted with Zn+ and O+ ions are studied via Rutherford backscattering spectroscopy based on the analysis of He2+-ion spectra with the use of the channeling technique. The doping-impurity redistribution is analyzed upon the formation of zinc-oxide nanoparticles. The sample surface morphology is examined by means of atomic-force microscopy and scanning electron microscopy under secondary-electron emission conditions. X-ray phase analysis of the implanted layers is carried out.

ZnO Nanoparticle Formation in Si by Co-Implantation of Zn+ and O+ Ions

ZnO nanoparticles (NPs) formed in Czochralski-grown n-type (100) silicon substrates have been studied. The NPs were formed by co-implantation of 64Zn+ and 16O+ ions followed by furnace annealing in neutral/inert atmospheres for 1h. High-resolution transmission electron microscopy (HR TEM) of cross-section samples enabled the structural properties of the near surface layers to be characterized after implantation and annealing. The distribution of implant profiles was analyzed by secondary ion mass-spectrometry (SIMS). The surface morphology was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Identification of the phase content of the materials was carried out by high-resolution X-ray diffraction in θ-2θ scanning mode. In as-implanted samples, a big amorphous layer was formed which destroyed the NPs beneath the surface. After furnace annealing from 600 up to 800°C, ZnO(102) NPs with a size of ~7nm were formed in the recrystallization layer. Furnace annealing at temperatures above 900 °C gave rise to a restructuring of the silicon surface and ZnO NPs formed on the sample surface. At temperatures above 1000 °C, out-diffusion of Zn from the sample occurred due to the large diffusion coefficient Zn at these temperatures.

A CVD Process for Producing Atomic Current Sources Based on 63Ni

A CVD process was developed for producing 63Ni-based atomic batteries by deposition of active 63Ni layers onto semiconductor silicon supports. Tetrakis(trifluorophosphine)nickel synthesized from 63Ni metal and phosphorus trifluoride was used as the volatile precursor. The influence of the support temperature and working pressure on the characteristics of the 63Ni coating was examined.

Study of the distribution profile of iron ions Implanted into silicon

Iron ions with energies of 90 and 250 keV and a dose of 1016 cm–2 are implanted into a silicon single crystal with the (110) orientation. The method of Rutherford backscattering in combination with channeling is used to study the distribution profiles of the introduced impurity and also the profiles of the distribution of radiation-induced defects in the crystal lattice. Experimental data are compared with the results of simulation performed using the TRIM software package. It is shown that, at an energy of 4.6 keV/nucleon, the average projected ranges coincide; however, at an energy of 1.6 keV/nucleon, the difference amounts to 35%. In addition, it is shown that the calculation incorrectly takes into account the dose dependence at energies of 1.6–4.6 keV/nucleon.

Iron ions distribution profile obtained by irradiating the silicon single crystal

Iron ions with energies of 90 and 250 keV and the irradiation dose of 1016 ions/cm2 and xenon ions with energies of 100 keV and dose 7,7×1014 cm-2, 200 keV and dose 2,6 × 1014 cm-2 were implanted in the single crystal of silicon (110). The distribution profiles of implanted impurity, as well as the distribution profiles of the radiation defects in the crystal lattice, were studied by the Rutherford backscattering method in combination with channeling. The experimental results were compared with the results of simulations of binary collisions of the Monte Carlo method in the TRIM program. It is shown that the difference between the experimental data and the calculation program TRIM is more than 35% in all cases.