G. N. Tolmachev

The synthesis mechanism of complex oxide films formed in dense RF — plasma by reactive sputtering of stoichiometric targets

The paper presents new experimental data on the synthesis and crystallization of complex oxide films produced by rf sputtering of ceramic targets. The deposition system has threshold states, the transition through which sets off a qualitative modification of its properties. The main feature of this modification is the appearance of a new structured system in plasma.

On the control of thin film growth by angular reflectometry near the brewster angle

The method of angular reflectometry is used to analyze the formation dynamics of layered structures on transparent substrates. This method is highly sensitive to changes in the parameters of a film structure at the early stage of formation thereof. It is based on the angular dependence of the reflected signal intensity near the Brewster angle and is almost independent of the state of the measuring facility. Experimental data obtained for multiferroic thin films on an isotropic crystalline Al2O3(001) substrate are presented. The films on the Al2O3(001) substrate are obtained by sputtering a Bi0.95Nd0.05FeO3 target for 5–600 s in an rf glow discharge initiated in oxygen.

Mechanism of the rf sputtering of mixed oxides

New experimental data on the growth mechanisms of multicomponent Pb(Zr,Ti)O3, (Ba,Sr)TiO3, and Y-Ba-Cu-O films in an rf discharge plasma are presented. An investigation of the spatial distribution of the radiated intensity of the sputtered particles in the rf plasma during the deposition of films of these mixed oxides in the epitaxial state reveals general laws governing their transport from the target to the substrate, which are stipulated by features of the negative glow of the rf discharge. The roles of external and internal parameters are examined from the standpoint of describing the mechanisms of the heteroepitaxial growth of mixed oxides.

Features of the spectra of optical emission from high-frequency discharge plasma during bismuth ferrite sputtering

Abstracthe spectra of optical emission from plasma of the RF discharge in oxygen during the sputtering of bismuth ferrite (BiFeO3) and iron-containing alloy targets have been studied. Two anomalously intense lines of emission from iron atoms at 613.6 and 306.7 nm have been observed during the sputtering of bismuth ferrite, which are much less pronounced in the case of metal targets. The lines of emission from bismuth atoms are completely absent. A mechanism responsible for excitation of the anomalous emission lines during the sputtering of BiFeO3 is proposed.

Spectra of X-ray emission from low-pressure gas discharge with runaway electrons

The spectra of X-ray emission from a low-pressure xenon discharge with runaway electrons and from a discharge in low-pressure oxygen with vanadium target have been studied. The X-ray energy spectrum from discharge can be adequately described in the framework of a theory of the intensity of continuous X-ray fluorescence.

Online in-situ control of lead zirconate titanate film growth in gas discharge chamber

Online in situ monitoring of the gas-discharge deposition of lead zirconate titanate Pb(ZrxTi1 − x)O3 (PZT) films onto a stainless steel substrate revealed oscillatory decay in the intensity of light with a wavelength of 0.640 μm specular reflected from the growing film. It is established that the parameters of the reflectance curves depend on the electric power deposited in discharge and correlate with the type of growing films (possessing pyrochlore or perovskite structures). Using the proposed method, it is possible to control technological parameters of the deposition process, which determine the physical characteristics of the obtained PZT films.

Heteroepitaxial growth of complex-oxide films from a self-organized system formed in a gas-discharge plasma

New experimental data on the characteristic features of the synthesis and crystallization of films of solid solutions of lead zirconate-titanate, deposited by means of rf diode sputtering of ceramic targets, are presented. Such a deposition system possesses threshold states, transition through which leads to a qualitative change in the processes occurring in the system and to the appearance of self-organization effects. The basic feature of this change is determined by the appearance of a new structured system, consisting of the sputtered particles and particles formed in the plasma, in the plasma of an rf discharge.

Optical anisotropy and dielectric parameters of (Ba0.5Sr0.5)Nb2O6 films on a Pt(111)/Si(001) substrate

Abstract(Ba0.5Sr0.5)Nb2O6 films were synthesized on a Pt(111)/Si(001) substrate by RF gas-discharge sputtering in pure oxygen atmosphere. It was found that the films have a dominant crystallographic orientation in the [001] direction and natural unipolarity, which was revealed through analysis of dielectric and piezoelectric parameters. It was demonstrated that the optical parameters of film material in the Ba0.5Sr0.5, Nb2O6/Pt(111)/Si(001) heterostructure match those typical for a (Ba0.5Sr0.5)Nb2O6 single crystal.

Method to control the optical parameters of thin transparent films using angle optical reflectometry

A way is suggested to determine the thickness and refractive index of films on an optically homogeneous substrate from the angular dependence of the intensity of H-polarized probing radiation reflected from the film. It is found that there is an angle at which a family of reflection curves taken of transparent films with the same refractive index and different thicknesses intersect (become degenerate). The tangent of this angle equals the refractive index of the film. The efficiency of this method is demonstrated with a series of BSN/MgO(001) films.

Peculiarities of film growth in glow discharge with runaway electrons

We have studied the properties of films deposited in gas discharge with a beam of runaway electrons and observed for the first time an anomalous behavior of the intensity of a probing light beam reflected from a film on substrate upon switching off of the discharge. The observed phenomenon is interpreted in the framework of a two-layer model of the film growth on a substrate, according to which an optically homogeneous surface layer of unknown nature appears on the film during growth in discharge and fully decomposes when the discharge is switched off.