At present, materials prepared by chemical vapor deposition technology are not only used in cutting tool materials, wear-resistant, heat-resistant, corrosion-resistant materials, special composite materials in the aerospace industry, atomic reactor materials, and biomedical materials, but also widely used in the preparation and synthesis of various powder materials, bulk materials, new crystal materials, ceramic fibers, and diamond films. In the field of thin film preparation technology for ferroelectric materials, insulating materials, magnetic materials, and optoelectronic materials as large-scale integrated circuit technology, it is even more indispensable.
Principles of CVD Technology
CVD technology is the process of introducing vapor containing gaseous or liquid reactants that make up the thin film elements and other gases required for the reaction into a reaction chamber, causing a chemical reaction on the substrate surface, and depositing solid products onto the surface to form a thin film.
It includes four main stages:
① The reaction gas diffuses towards the surface of the material;
② The reactive gas adsorbs onto the surface of the material;
③ Chemical reactions occur on the surface of materials;
④ Gaseous by-products detach from the surface of the material.
Characteristics of CVD technology
The film layer formed by CVD technology is dense and uniform, with a strong bond between the film layer and the substrate, easy control of the film composition, fast deposition rate, and stable film quality. Some special film layers also have excellent optical, thermal, and electrical properties, making them easy to achieve mass production. However, the deposition temperature of CVD is usually very high, between 900 ℃ and 2000 ℃, which can easily cause deformation of parts and changes in microstructure, thereby reducing the mechanical properties of the body material and weakening the bonding force between the body material and the coating, limiting the selection of substrates, deposition layers, or the quality of the resulting workpiece. At present, CVD technology is developing towards two directions: medium and low temperature and high vacuum, and is combined with plasma, laser, ultrasound and other technologies to form many new CVD technologies.
