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Radio frequency magnetron sputtering, also called RF magnetron sputtering is a process that is used to make thin film, especially when using materials that are non-conductive. In this process, a thin film is grown on a substrate that is placed in a vacuum chamber. Powerful magnets are used to ionize the target material and encourage it to settle on the substrate in the form of a thin film.
The first step in the RF magnetron sputtering process is to place a substrate material in a vacuum chamber. The air is then removed, and the target material, the material that will comprise the thin film, is released into the chamber in the form of a gas. Particles of this material are ionized through the use of powerful magnets. Now in the form of plasma, the negatively charged target material lines up on the substrate to form a thin film. Thin films can range in thickness from a few to a few hundred atoms or molecules.
The magnets help speed up the growth of the thin film because magnetizing the atoms helps to increase the percentage of target material that becomes ionized. Ionized atoms are more likely to interact with the other particles involved in the thin film process and are, therefore, more likely to settle on the substrate. This increases the efficiency of the thin film process, allowing them to grow more quickly and at lower pressures.
The RF magnetron sputtering process is especially useful for making thin films out of materials that are non-conducting. These materials may have more difficulty forming into a thin film because they become positively charged without the use of magnetism. Atoms with a positive charge will slow down the sputtering process and can “poison” other particles of the target material, further slowing down the process.
Magnetron sputtering can be used with conducting or non-conducting materials, while a related process, called diode (DC) magnetron sputtering, only works with conducting materials. DC magnetron sputtering is often done at higher pressures, which can be difficult to maintain. The lower pressures used in RF magnetron sputtering are possible because of the high percentage of ionized particles in the vacuum chamber.