OPTIMIZATION OF THE DEPOSITION PROCESS OF THIN METAL FILMS IN GLOW DISCHARGE WITH HOLLOW CATHODE
Bolotov Maksym, Chernihiv National University of Technology (95 Shevchenka Str., 14027 Chernihiv, Ukraine)
Urgency of the research. Recently, for generating the necessary flows of atoms and molecules to obtain of thin metal films the low-temperature plasma of abnormal glow discharge with cold cathode in crossed electric and magnetic fields have gained widespread use. The high sputtering rate, no overheating of the substrate surface and small degree of films contamination make this method very effective source of directed metal atoms and ions applicable for deposition.
Target setting. Currently, the most common methods of film deposition is PVD methods (physical vapor deposition) where the atoms and molecules of metal, necessary for the coating synthesis are obtained by the target evaporation processes. The experience of such technologies applying for a long period of time in the industrial conditions allowed to determine the basic disadvantages, mainly related to the low rate of deposition, low coating homogeneity, poor adhesion with the substrate, limitation of treated surfaces etc.
Actual scientific researches and issues analysis. In an earlier study on the application of hollow cathode glow discharge in various technological processes have allowed determining the main advantages, primarily associated with simple design, durability of target (cathode) and cheapest equipment compared to the magnetron systems.
Uninvestigatigated parts of general matters defining. At the same time, virtually no data concerning the application as a source of sputtering particles for the growing of thin metal films on the dielectric substrates of low-temperature plasma hollow cathode glow discharge without applied magnetic field at the traditional pressures of 1 - 100 Pa.
The research objective. The process of metal film forming and growing are defined by the coherence of a number of parameters, such as shape, size and the spatial position of the target and substrate, pressure in the vacuum chamber, current and voltage in the discharge circuit, deposition time and so on. All this complicates the deposition processes. In this regard, the aim of this work is to optimize the deposition processes of thin metal film in the hollow cathode glow discharge by selecting from the totality of parameters the most optimal, ie parameters that most strongly related to the film thickness.
The statement of basic materials. Determination of these parameters was performed by evaluating of coefficients at the corresponding factors in statistical models built by means of mathematical experiment planning. The set of parameters with the possibility of determining their quantitative assessment was introduced in the model. The optimization parameter was the thickness of the copper film (δ, μm) deposited on a glass substrate. As variable factors were taken, cathode-substrate distance Lk-s (X1), discharge current Id (X2), the value of the pressure in the discharge chamber P (X3) and deposition time t (X4).
Conclusions. The analysis found that the optimization parameter (thickness of copper film) is described by the influence of complex of studied parameters on 84%, rest 16% variations provided by the influence of other not included in the model factors.
mathematical experiment planning, glow discharge, hollow cathode, thin film coating, the regression model
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