Till rather recent time for thin films receiving used mainly processes of evaporation and condensation of substances in high vacuum, so-called thermal vacuum method. Thermal vacuum method is characterized by simplicity and high speeds of sedimentation, however does not provide sufficient reproducibility of films properties of compound structure, does not provide good adhesion of covering, does not allow evaporating refractory materials. Besides at a plenty of components of depositing coverings they render essential influence against each other at evaporation that does not allow calculating the evaporation mode. In practice process of evaporation are limited to the covering deposition consisting from 1…3 components.
Expansion of the nomenclature of used materials has essentially raised interest to films receiving by ionic dispersion. This method allows depositing the film of metals, including refractory, alloys, including multicomponent, semiconductors and semi-conductor connections.
However wide application of ionic dispersion processes restrained in the low speeds of sedimentation (0.2…1.5 nm/s), presence of a high voltage (2…5 kV), and also intensive heating of substrates and film as a result of bombardment by high-energy secondary electrons.
Position has essentially changed after occurrence of highly effective magnetron sputtering systems. In these devices electrons, emitted from the target under action of ionic bombardment, are grasped by a magnetic field and make complex cycloidal movement on the closed trajectories near to a surface of a target. High current density (100…200 мА/sm2) and big specific power (80…100 watt/sm2) sharply (in 50…100 times) increase dispersion speed of materials in magnetron system.
In magnetron atomizing systems (MAS) the degree of ionization of neutral gas comes nearer to 100 % that allows achieving high current density on a target. Owing to this dispersion speed comes nearer to speed of electron beam evaporation. Maximum dispersion (sedimentation) speed is defined by heat conductivity of a sprayed material and conditions of target cooling.
Reception of homogeneous on thickness coverings is achieved by the correct choice of the sprayed target size, distances from the target up to the substrate, and also corresponding moving of the substrate in relation to the sprayed atoms stream.
However magnetron sputtering systems, having a number of advantages in comparison with other systems of dispersion and evaporation, have also the disadvantages. One of the main disadvantages of magnetron sputtering system is the small use factor of material with which the problem of uniformity of target dispersion is closely connected. The use factor of material can be increased by choice of the certain geometry target or applying scanning magnetic field. There are two ways of moving of magnetic field on a target surface: electromagnetic and mechanical. In the first case around of the target an electromagnet is installed which creates an additional variable magnetic field, perpendicular surfaces of a target. Application of an additional variable field makes deformation of the basic field. Uniformity of target dispersion can be increased considerably, using the multicellular electromagnetic system feeding from alternating current network. Methods of mechanical scanning of plasma on a target moving of magnetic system are rather various and are realized basically at use of constant magnets. Rotary or reciprocating moving of magnetic system provides uniform dispersion almost of the whole surface of flat and cylindrical targets. Both of methods have a number of disadvantages and advantages. In the first case difficult calculation of magnetic system, in the second - complexity of designs of similar magnetron systems is represented.
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