What does vapor deposition mean chemical vapor deposition principle

The implication is the deposition of solid products of chemical reactions in the gas phase onto the surface. The CVD device consists of the following components; Reactant ** system, gas phase reactor, gas flow transfer system. The reactants are mostly metal chlorides, which are first heated to a certain temperature to reach a sufficiently high vapor pressure, and then fed into the reactor with carrier gas (usually AR or H2).

If a metal cannot form a high-pressure chloride vapor, it is replaced by organometallic compounds. Inside the reactor, the coated material is either suspended with wire, placed on a flat surface, or sunk in the fluidized bed of the powder, or itself is a particle in the fluidized bed. In a chemical reactor, the product is deposited on the surface of the coated object, and the exhaust gas (mostly HCl or HF) is directed to alkaline absorption or cold trap.

Deposition reactions can be considered as reduction, pyrolysis and substitution. CVD reactions can be divided into cold-wall reactions and hot-wall reactions. In a hot-wall reaction, the chemical reaction takes place in the same chamber as the coated object.

A thin film is applied to the surface of the coated object and the inner wall of the reaction chamber. In the hot-wall reactor, only the coated material is heated, and the reactants are introduced separately.

Chemical vapor deposition (CVD) is a process technology in which reactive substances undergo chemical reactions under gaseous conditions to generate solid substances that are deposited on the surface of heated solid substrates, and then prepare solid materials. It is essentially a gaseous mass transfer process that falls under the category of atoms. The opposite is physical vapor deposition (PVD).

It is an electroplating method invented by the Japanese epson company, the basic principle of which is to change the electroplating substance into meteorology through a certain method, and then condense on the surface of the electroplated substance, so that the electroplating layer obtained is more uniform and dense, because the equipment is complex and expensive, and there do not seem to be many companies that have mastered this technology in China.

Tool coating knowledge sharing, do you know what physical vapor deposition is?

Chemical vapor deposition principle: Chemical vapor deposition (CVD) is the process of using gaseous or vapor substances to react on the gas phase or gas-solid interface to form solid deposits.

Process: The chemical vapor deposition process is divided into three important stages: the diffusion of the reaction gas to the surface of the matrix, the adsorption of the reaction gas on the surface of the matrix, the chemical reaction on the surface of the matrix to form a solid deposit, and the resulting gas-phase by-products from the surface of the matrix.

The most common chemical vapor sedimentation reactions are: thermal decomposition reaction, chemical synthesis reaction and chemical transport reaction.

The development of chemical vapor deposition is inseparable from its own characteristics, which are as follows:

1) There are many types of deposits: metallic films, non-metallic films, multi-component alloy films, and ceramic or compound layers can also be prepared as required.

2) The CVD reaction is carried out at atmospheric pressure or low vacuum, and the diffraction of the coating is good, and it can be evenly plated for deep holes and fine holes of complex surfaces or workpieces.

3) It can obtain a thin film coating with high purity, good compactness, small residual stress and good crystallization.

4) Because the temperature of the film is much lower than the melting point of the film material, a film with high purity and complete crystallization can be obtained, which is necessary for some semiconductor coatings.

5) By adjusting the parameters of deposition, the chemical composition, morphology, crystal structure and grain rise of the cladding can be effectively controlled.

6) The equipment is simple, easy to operate and maintain.

7) The reaction temperature is too high, generally 850-1100, and many matrix materials cannot withstand the high temperature of CVD. Plasma or laser-assisted technology can be used to reduce the deposition temperature.

First, the characteristics of the two are different:

1. Characteristics of physical vapor deposition: the energy of deposited particles in physical vapor deposition is adjustable and the reactivity is high. By using plasma or ion beam mediation, the required energy of deposited particles can be obtained for coating and improving the quality of the film.

The reactivity is increased by the non-equilibrium process of the plasma.

2. The characteristics of chemical vapor deposition method: high purity, good compactness and residual stress can be obtained.

Small, well-crystalline thin film coating. Due to the mutual diffusion of reaction gases, reaction products and substrates, a well-adhesive film can be obtained, which is very important for surface reinforcement films such as surface passivation, corrosion resistance and wear resistance.

2. The essence of the two is different:

1. The essence of physical vapor deposition method: the method of vaporizing the coating material by physical methods (such as evaporation, sputtering, etc.) and depositing the film on the surface of the substrate.

2. The essence of chemical vapor deposition: the process of using gaseous or vapor substances to react on the gas phase or gas-solid interface to form solid deposits.

Third, the application of the two is different:

1. Application of physical vapor deposition: physical vapor deposition technology has been widely used in all walks of life, and many technologies have been industrialized.

2. Application of chemical vapor deposition: The coating products of chemical vapor deposition involve many practical fields.

It is too general, CVD and PCD contain a variety of preparation methods, and the structure and properties of the films prepared by different preparation methods are not the same. However, the stability of PVD is better than that of the general CVD method, but the PVD growth is relatively fast by obtaining the membrane of the membrane in the following ways.

Principle: Chemical vapor deposition.

The technology is the application of gaseous substances to produce chemical reactions on solids.

and transport reactions and other processes to produce solid deposits, which roughly consist of three steps:

1) Formation of volatile substances;

2) transfer the above materials to the sedimentary area;

3) Creates a chemical reaction on a solid and produces a solid substance. The most basic chemical vapor deposition reactions include thermal decomposition reactions, chemical synthesis reactions, and chemical transport reactions.

Applications: Modern science and technology require the use of a large number of new inorganic materials with different functions.

It must be a high-purity material, or a doped material formed by intentionally mixing some impurities into the high-purity reed dust material. However, many of the preparation methods that we are familiar with in the past, such as high-temperature melting, precipitation and crystallization in aqueous solutions, are often difficult to meet these requirements, and it is difficult to ensure a high-purity product. Therefore, the synthesis of new inorganic materials has become a major topic in modern materials science.

In the process of chemical vapor deposition, there is a chemical reaction in which a variety of materials react with each other to form new materials.

There is no chemical reaction in physical vapor deposition, only the morphology of the material changes.

The physical vapor deposition technology has a simple process, improves the environment, no pollution, less consumables, uniform and dense film formation, and strong binding force with the matrix. Disadvantages: The binding force of the film is weak, the coating is not wear-resistant, and there is directionality.

Chemical impurities are difficult to remove. Advantages: It can make metallic films, non-metallic films, and multi-component alloy films according to requirements, with fast film-forming speed and good diffraction of the film.

Chemical vapor deposition can be classified according to the deposition process and feedstock.

According to the process, it can be divided into: metal-organic compound chemical vapor deposition technology (MOCVD), plasma chemical vapor deposition (PCVD), laser chemical vapor deposition, low-pressure chemical vapor deposition, ultra-vacuum chemical vapor deposition, ultrasonic chemical vapor deposition (UWCV).

According to the raw materials, it can be divided into chemical vapor deposition SI N, SI, SI C, phosphorus, boron, etc.