Chemical Vapor Deposition (CVD). As the name implies, it is a technique that utilizes gaseous precursor reactants to generate solid films by means of atomic and intermolecular chemical reactions. Unlike PVD, the CVD process is mostly carried out in a higher pressure (lower vacuum) environment, with the higher pressure being used primarily to increase the deposition rate of the film. Chemical vapor deposition can be categorized into general CVD (also known as thermal CVD) and plasma-enhanced chemical vapor deposition (Plasma-Enhanced Chemical Vapor Deposition. PECVD) according to whether plasma is involved in the deposition process. This section focuses on PECVD technology including the PECVD process and commonly used PECVD equipment and working principle.
Plasma-enhanced chemical vapor deposition is a thin-film chemical vapor deposition technique that utilizes glow discharge plasma to exert an influence on the deposition process while the low-pressure chemical vapor deposition process is taking place. In this sense, conventional CVD technology relies on higher substrate temperatures to realize the chemical reaction between gas phase substances and the deposition of thin films, and thus can be called thermal CVD technology.
In the PECVD device, the working gas pressure is about 5~500 Pa, and the density of electrons and ions can reach 109~1012/cm3, while the average energy of the electrons can reach 1~10 eV. What distinguishes the PECVD method from other CVD methods is that the plasma contains a large number of high-energy electrons, which can provide the activation energy needed for the chemical vapor deposition process. The collision of electrons and gas-phase molecules can promote the decomposition, chemosynthesis, excitation and ionization processes of gas molecules, generating highly reactive chemical groups, thus significantly reducing the temperature range of CVD thin film deposition, making it possible to realize the CVD process, which is originally required to be carried out at high temperatures, at low temperatures. The advantage of low temperature thin film deposition is that it can avoid unnecessary diffusion and chemical reaction between the film and the substrate, structural changes and deterioration of the film or the substrate material, and large thermal stresses in the film and the substrate.
–This article is released by vacuum coating machine manufacturer Guangdong Zhenhua
Post time: Apr-18-2024