What is the role of plasma in the thin film deposition?In all methods of physical vapor deposition of plasma used? In chemical vapor deposition, how?
Physical Vapor Deposition means all techniques, where a solid target is being evaporated by physical methods. That doesn't necessarily require plasma, e.g. when you use thermal evaporation: Here you only need a source of thermal energy to heat a target material to it's evaporating point. Also laser or electron beam evaporation work without plasma. Plasma is needed for sputtering techniques, because here the evaporation occurs due to the kinetic energy of the impact of ions.
The major advantage compare to simple chemical vapor deposition is that plasma-enhanced chemical vapor deposition PECVD can operate at much lower temperature.plasma polymerization as example, which is essentially a plasma enhanced chemical vapor deposition process which take place in a low pressure and low temperature plasma that is produced by a glow discharge through an organic gas or vapor.In the plasma polymerization process, a monomers gas is pumped into a vacuum chamber where it is polymerized by plasma to form a thin, clear coating. The monomer starts out as a liquid; it is converted to a gas in an evaporator and is pumped into the vacuum chamber. A glow discharge initiates polymerization. The excited electrons created in the glow discharge ionize the monomer molecules. The monomer molecules break apart (fractionate) creating free electrons, ions, exited molecules and radicals. The radicals adsorb, condense, and polymerize on the substrate.
all of techniques have the aim to control film properties. 'New material properties. By controlling the composition and microstructure of the films, new properties can be achieved. So deposition under well defined conditions is needed. Vacuum techniques and plasma technologies are there to create the right conditions of material grows.
Parameters to be controlled are various, and their effects on the material complex.
Each technique (EB evaporation, IBAD, Sputtering (DC, rf, HIPIMS) PECVD (10 KHz to 2,45 GHz), laser assisted processing and many more) has its advantages for dedicated applications from optoelectronics to mechanical engineering.
welcome in this huge and still sexy topic
it is all about the quality of the energy of the deposited atoms/molecules.
It is mainly a non-equilibrium processing. (to have the variety of properties).
The control of the electrons and the ions in the different plasmas will make the difference between the various techniques.
https://www.researchgate.net/publication/272257387_Novel_strategy_for_low-temperature_high-rate_growth_of_dense_hard_and_stress-free_refractory_ceramic_thin_films
perfect article with all the basics of thin film coating technology.
Article Novel strategy for low-temperature, high-rate growth of dens...
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