I. I. Shkarban

High-frequency ion sources of inert and chemically active gases

A description of the principles of operation and the main characteristics of high-frequency ion sources that can function on inert and molecular gases, in particular, oxygen, nitrogen, and their mixtures including air, and also on the basis of complex molecular compounds are given, which allows one to use them in various technological processes and in outer space as efficient ion thrusters.

Features of sputtering of nitrides and their components

The sputtering behaviour of hexagonal or wurtzite polycrystal nitrides of boron, aluminium, and gallium was explored employing methods of molecular dynamics. The sputtering yield Y of nitrides and the average energy Ē 1 of emitted particles were studied as dependent on the mass m 1 of bombarding He, Li, B, N, Ne, Al, Ar, Ni, Ga, Kr, and Xe ions with the initial energy E 0 between 200 and 10,000 eV. Y(m 1) and Ē 1(m 1) were researched upon for preferential sputtering of nitride components at low E 0. It was revealed that the ratio between the sputtering yield of the light component and that of the heavy one depends on ion energy and mass. At E 0=200 eV and m 1=40, the ratio for BN, AlN, and GaN amounts to 1.2, 2.2, and 2.4, respectively. For nitride components, an anomalous dependence of sputtering on ion mass was found, its maximum occurring at a certain ratio m 2/m 1, where m 2 is the averagè mass of two nitride components.

Inelastic losses of low-energy ions transmitted through thin films

Abstract Experimental results on inelastic losses by ions of energy 10 3 −10 4 eV transmitted through thin solid films are presented and discussed. The C, Cu, Ag, and Ni films (from 35 to 900 A thick) have been bombarded by He + , Ne + and Ar + ions. The angular and temperature dependence of energy losses of transmitted ions have been studied. Experimentally obtained values of inelastic losses appear to agree with the Lindhard-Scharff-Schott (LSS) theory. A step-like increase in inelastic energy losses has been observed for He + ions transmitted through the Ni films undergoing ferro- to paramagnetic phase transition.

Fractal-like structures formed in the interelectrode gap during grid ion-source electrode sputtering

Carbon-carbon electrode sputtering in the accelerating negatively charged grid of an ion source is investigated. It is ascertained that complicated fractal-like structures of sputtered material atoms are formed during the sputtering process. Possible conditions and causes underlying their formation and probable models of growth thereof caused by similar physical processes are discussed.

Nanostructured oxide membranes

Porous aluminum (Al 99.99%) foil membranes prepared by electrochemical anodizing and subsequent removing the continuous barrier layer by ion-plasma irradiation are described. As a result, Al2O3 membranes about 2–5 μm thick with regular arrangement of channels have been obtained. The possibility has been shown of regulation of a channel diameter in a range of 20–100 nm by changing the oxidation conditions. The experimental dependences of Al and Al2O3 sputtering coefficients on the xenon ion energy (100–400 eV) and the angle of incidence have been obtained.

Secondary emission of carbon ions from graphite nanocrystallites

Emission of secondary C+ ions from the surface of well-oriented graphite nanocrystallites irradiated with 10 keV Ar+ ions has been studied. The energy distribution of emitted secondary ions has been measured. It has been found that the form of energy distribution and the energy corresponding to the maximum of distribution Emax depend on the polar angle θ of C+ ion emission. The linear dependence of energy in the maximum of energy spectrum of single-charged secondar y carbon ions on the polar angle of their emission Emax(θ) has been obtained. The mechanism responsible for the observed features of the energy spectra is discussed.

Radiation resistance of boron nitride and related ceramics to low-energy electron irradiation

The radiation resistance of heat-proof ceramics based on boron nitride (BN + Si3N4 and BN + SiO2), which are proposed to be used as structural materials in space ion engines, to low-energy electron irradiation has been investigated.

Solid Nanomembrane Manufacture Using Ion-Plasma Action

A process of manufacture of porous membranes made of aluminum foil (Al 99.99%) by the method of electrochemical anodic oxidation followed by a continuous barrier layer removal with ion-plasma irradiation is described. The membranes having a 8 mm diameter made from AL2O3 with a thickness from 2 to 5 microns thick with a regular channel arrangement are obtained. A possibility to change the channel diameter in the range of 20–100 nm by adjusting voltage and temperature during the oxidation is shown. We present the experimental dependencies of aluminum and aluminum oxide sputtering coefficients on the energy and incidence angle of xenon ions within the energy range of 100…400 eV.