Deposition
Deposition is a set of processes used to create thin or thick layers of a substance atom-by-atom or molecule by molecule on a solid surface. The created layer deposits as a coating on a surface and changes the properties of the substrate surface depending on the application. The thickness of the deposited layers in this process, depending on the coating method and the type of material, can be in the range of one atom (nanometer) to several millimeters.
There are several methods for creating a layer of different materials on different surfaces such as spraying, spin coating, plating and vacuum deposition methods that are performed from the vapor phase of the target material. In the following, we will introduce some deposition methods:
Spin Coating
Spin coating is used to deposit a thin layer of the target material on a flat substrate. Usually a small amount of liquid material is poured on the center of the substrate and then the substrate begins to rotate so that the material with a certain density is spread on the substrate by centrifugal force and coat it.
Electroplating
Electroplating is a surface coating method in which a metal is coated on a conductive surface. This method is cheaper than other methods and is used to conductivity improvement, decorative applications and corrosion resistance.
Spraying
In the spraying process, particles or droplets of the target material are sprayed on the substrate to deposit on it and form a layer.
Vacuum Deposition
If the coating process is performed in an environment with a pressure lower than atmospheric (vacuum), it is called vacuum deposition. Vacuum reduces the density of atoms in the environment and thus increases the mean free path of atoms. In addition, vacuuming the environment can remove undesirable gas atoms in the deposition environment and bring the chemical composition of the layers closer to the desired chemical formula.
Vapor Deposition Method
This method is divided into two categories of chemical vapor deposition (CVD) and physical vapor deposition (PVD) depending on the desired vapor deposition process.
In the CVD process, the suspended particles in the coating chamber (chemical vapors) are subjected to chemical processes such as composition and decomposition, and finally settle as a dense and solid layer on the desired surface. In this coating method, volatile by-products are usually created, which are removed from the chamber by the gas flow.
If to improve chemical reactions plasma is used in the CVD process, it is called plasma-enhanced CVD (PECVD).
In the PVD method, the target material, which is solid, is converted from solid to vapor phase, bombards the surface and settles on the substrate. According to the way the solid is converted to the vapor phase, the PVD method is divided into different categories, which are:
Thermal Evaporation Deposition
In this method, thermal evaporation method, the material reaches the melting point temperature due to the heat generated due to the passage of high electric current through a boat or basket and then evaporates and settles on the substrate as a thin film. Among the Vac Coat’s products, DTT and carbon coaters (DCR & DCT) models are used to thermal evaporation of the metals and carbons respectively.
Pulsed Laser Deposition (PLD)
In this method, pulsed laser deposition, the high-energy pulsed laser strikes the surface of the target material, causing its molecules to be removed. These molecules then sit on the substrate surface. PLD system manufactured by Vac Coat Ltd. in addition to use for PLD process, is equipped with thermal evaporation electrodes to do thermal evaporation deposition.
Sputtering Deposition
In this method, by bombarding the surface of the target material with high-energy ions of argon gas, the molecules of the target surface are removed and deposit on the substrate. There are several models of VacCoat’s device which can be used for sputtering deposition. The devices are in different models such as DST1, DST3 and DSR1 depending on the number of cathode, ultimate pressure, power supply (RF or DC).
Electron Gun Deposition
In this method, by bombarding the material with billions of high kinetic energy electrons and increasing the temperature of the material until evaporation temperature, a thin film of the material will be deposited.
The products of Vac Coat Ltd. are vacuum deposition system. Our devices use different type of the PVD methods to deposit thin films. If you intend to do deposition by PVD method or for more information about the products of Vac Coat Ltd., refer to the company’s website.
Some of Vac Coat Products