Introduction to PECVD principle

PECVD literally means plasma (P) enhanced (E) chemical vapor deposition (CVD). The reaction gas is transformed into plasma under the action of equipment radio frequency (RF), so as to carry out chemical reaction and generate the required membrane materials. The reaction temperature is relatively low. The film-forming compactness is worse than that of furnace tube. But it is efficient and easy to maintain.

Generally speaking, when PECVD technology is used to prepare thin film materials, the growth of thin films mainly includes the following three basic processes:
First, in the non-equilibrium plasma, the electrons react with the reaction gas, which decomposes the reaction gas to form a mixture of ions and active groups;

Secondly, various active groups diffuse and transport to the film growth surface and the tube wall, and secondary reactions between reactants occur at the same time;

Finally, various primary and secondary reaction products reaching the growth surface are adsorbed and react with the surface, accompanied by the re release of gaseous molecules.
Gases (such as SiH4, NH3, N2, etc.) are ionized into ions under the action of RF power supply; After many collisions, a large number of sih3-, h- and other active groups were produced; These active groups are adsorbed on the substrate or replace the H atoms on the surface of the substrate; The adsorbed atoms migrate on the surface of the substrate under the action of their own kinetic energy and substrate temperature, and choose the point with the lowest energy to stabilize; At the same time, the atoms on the substrate constantly break away from the bondage of the surrounding atoms and enter the plasma to achieve dynamic equilibrium; When the atomic deposition speed is greater than the escape speed, we can continuously deposit the required thin films on the surface of the substrate.