Свойства оксидных покрытий, полученных с помощью дуального магнетрона
Дипломная работа - Физика
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are shown insufficiently. The absence of these data often leads to incomplete use and even misuse of those opportunities which are inherent thin-layer coatings.of thin layers of a new part of applied optics, obtained fast development from the middle of 20 centuries. As a stimulus to this successful is the practical use of the phenomena of interference and polarization of light in thin transparent layers, which radically changes optical and other properties of surface glasses or other optical environments. Material scientists have begun to realize more distinctly that special role which the free surface plays and borders of section in materials in a complex of its service properties.practical use of this circumstance has allowed to develop ways of updating of a surface of materials, and among them the most effective - depositing a thin-film 0,01-50 microns of coatings from various materials with an adjusted structure and physicomechanical and chemical properties. means of such coverings it is possible to significally change mechanical, optical, electric, magnetic, thermal and chemical properties of an initial material, obtaining products with required properties.the most perspective methods of sputtering coverings are vacuum ionic-plasma methods. For obtaining oxide coverings the HF-dispersion of dielectrics and magnetron sputtering systems are used, where besides inert gas active gas (oxygen) is also employed.sputtering of oxide films on a direct current is inefficiently because of oxide film formation on the cathode, that leads to the reduction of velocity of etching the cathode. Also charging oxide film surfaces by the positive ions bombarding a surface, and the further dispersion becomes impossible because ions from plasma are not attractive to the target.disadvantageous can be reduced due to periodic unloading the cathode, for example, using the generator of an alternating current. However it does not prevent the sedimentation of insulating a material on walls of the chamber - a problem known as the disappearing anode. High - frequency dispersion is not comprehensible because of low velocity of sputtering desirable materials. The Dual Magnetron System allows to eliminate these effects.
. The construction of the dual magnetron system (DMS)device concerns plasma technology and is designed for sputtering on a surface of firm bodies, films from metals and their connections synthesized as a result of atoms interaction, sputtered from a surface of the metal cathode, and the gas environment. The main principle of dual magnetron sputtering systems work is the following:
Figure1. The dual magnetron system
1-Planar magnetrons 2- Magnetic system case 3- The magnetic shunt 4- Insulators 5- The case of planar magnetron 6- Constant magnets 7- Target
the ground and one of targets positive pressure is submitted, and between the ground and other target the negative pressure is submitted. As a result we always have pure (un oxidized) anode and constant conditions on the anode. This is very important!, one magnetron everyone half period is cathode, and another - the anode. For that time while one magnetron works, another is cleared of a dielectric film and there is a neutralization of a positive volume charge. Then the polarity of pressure on magnetron changes.to the fact the dielectric film is not formed on magnetrons, the system works more stably: there is no blinking, flashes, magnetrons do not sparkle, the velocity of sputtering of a material considerably increases. As dual magnetron works stably, the quality of sputtered coatings is higher than with magnetron on a direct current because there is no opportunity of hitting a substrate of large impregnations of a sprayed material.from the magnetron construction there are several other facilities in the work:
) Ionic-plasma installation "Jasper" is designed for sputter-deposition modifying coatings on a surface of solid bodies by means of the magnetron plasma the discharge and the beams of the accelerated ions.
) By means of the CP-2000 spectrophotometer optical characteristics (transmission factor) of films, obtained by means of three these designs were investigated. The action principle of spectrophotometer is based on the measurement of the ratio of two light streams: the light stream passed through the investigated sample, and a flux falling on investigated sample.
. Experimental procedurethe experiment various designs of magnetron systems were located in the working part of the facility`s chamber of ionic-plasma drawing coatings "Iashma". The deposition of samples was done, using three designs, for detecting the optimal one which will provide the maximal velocity of sputtering and high quality of a covering.the comparing quality of films , obtained by means of dual magnetron sputtering systems with the built-in metal shunt and without it, as well with the help of the planar magnetron, depositing occured at identical modes. Films were deposited on glass substrates in the atmosphere of a mixture of argon and oxygen with the use of the titanic cathode.the measurement of thickness of oxide films, the photometric method was used. This method is usually used for the definition of thickness of non-absorbent coatings. It is based on the effect of waves interference in films whose thickness is commensurable with the length of a wave. In case of non-absorbent films on a dielectric substrate, the interference leads to effects of colouring.a photometric attachment, the velocity of depositing coatings in case of use dual magnetron designs with an additional element and without it, as well as with thehelp of the design planar magnetron, was measured., by means of spectrophotometra 2000 optical characteristics (transmission factor) of films were investigated, obtained by means of these three designs.
. The comparison of deposition ratessputtering of oxide layer took places gradually. Each layer corresponded the desktop passage with substrates under magnetron system. Therefore deposition rates can be defined by dividing geometrical thickness on the number of passes by means of which the necessary thickness obtained. The comparative diagram of dependences on velocity film sputtering from a number of passes of a table with the sample are presented in fig. 2.
. Dependence on indications of a photometric attachment on a number of passes:
-film which was sputtered by means of dual magnetron ( V = 6.593 nm/ pass)
-film sputtered with the help of dual magnetron with an additional element ( V = 5.733 nm/ pass)
-film which was sputtered by means of planar magnetron. ( V = 1.481 nm/ pass)
figure 2 it is obvious, that velocities of film sputtering obtained by means of a dual design, are 3 times higher than by means of the planar magnetron. The sputtering by means of a dual design Is more quickly than by means of a dual design with an additional element, but the design with the shunt provides stable burning the discharge and precludes from the burning of plasma in an interval between magnetrons.
. The research of oxide film characteristics spectrophotometer CP-2000,the principle of which is based on measuring of the ratio of two light streams: the light flux passed through investigated sample, and a stream falling on investigated sample ,research of optical characteristics was carried out: the dependence of factor transmission of the investigated sample on length of a wave was measured.
3. The spectrum of sample received by means of Dual МSS~ 85 % T - transmission factor
? = 421 nm ? - wavelengthspectrum is presented in fig. 3. It is visible, that for the sample obtained by means of a dual design, the factor of transmission constitutes about 85 %. For other samples the transmission factor is also equal approximately 85 %. From this it follows that optical characteristics of coverings obtained by means of different designs, are practically identical. the given work we consider ways of obtaining oxide films by means of magnetron depositions. Also, the design and a principle of dual magnetron work have been considered, and disadvantages and advantages of the given systems have been shown.the obtained results it is visible that the velocity of sputtering TiO2 by means of DMSS is higher, than using the planar magnetron, at the preservation of identical optical characteristics. By comparing two designs of dual magnetron, the preference should be given to designs with the shunt because additional element provides stable burning the category and also precludes from the burning of plasma in an interval between magnetrons.