In general CVD, a chemical reaction occurs between the atoms (molecules) of the raw material gas, and its products are deposited on the film surface , while in PECVD , a high-voltage electric field is set in the reaction chamber, and the reaction gas is excited in the high-voltage electric field to form very active excited molecules, atoms, The plasma composed of ions and atomic groups greatly accelerates the gas reaction, increases the CVD film formation rate, reduces the film formation temperature, and is convenient for production and application. PECVD is currently one of the CVD methods most concerned by material workers .
Schematic diagram of the principle of PECVD . The vertical reactor uses Gordon to generate glow discharge plasma , which is often used to deposit thin films such as silicon nitride. It can form a film at a low temperature of 350~400°C with a deposition rate of 50~100nm/min. The characteristics of PECVD technology are as follows:
(1) Low deposition temperature
For example, PECVD deposits TiN film, the film formation temperature is only 500°C, while the traditional CVD is about 1000 °C , so it can be deposited on materials that are not resistant to high temperatures .
(2) The bonding strength between the film and the substrate is high
This is due to the sputtering and bombardment effect .
(3) Fast film forming speed
When other conditions are the same, the deposition speed is faster than the traditional CVD process.
(4) The range of film materials that can be made
Due to the excitation of the plasma, the film-forming material that is difficult to react is deposited and formed into a film.
