Coating Methods For Optical Thin Film Pt. 2
Optical Thin Film Coating is an Essential Service
Hello, and welcome back to our blog! Here at Newport Thin Film Laboratory, we want to deliver the best thin film coating services that we possibly can. As anyone who has dealt with thin film already knows, the processes used to apply these films must be a precise and tightly controlled. In our previous post, we covered two of the techniques used to apply optical thin film to surfaces and, in today’s post, we are going to cover the last few techniques so that all of our readers have a better idea of how thin film is applied to various devices. If at the end of this blog you still have questions about how we apply thin film layers, please visit our website or contact us. We would be more than happy to answer any and all questions as they relate to our company. If you feel that you already have a firm grasp on our services, continue reading below to learn a little more about optical thin film application techniques.
Optical Thin Film is Thin, Really Thin
Although the average person is largely unaware of thin film, these coatings are in a wide variety of items that people use every single day. LED lights, automobiles, televisions, and smartphones all utilize thin film coatings and could not perform their functions properly without them. Below, we have listed a few of the methods used to apply thin film to these devices.
- Magnetron Sputtering: This application process is utilized mostly in architectural window glass coating. Utilizing this process, workers are able to coat hundreds of square feet of surface area per minute. This process accomplishes this by utilizing cathode assemblies containing magnets with the face of these cathodes containing a plate of coating material known as a target. During the application process, the chamber is flooded with argon and a voltage is applied to the cathode assembly while electrons are contained in front of the cathode by the magnetic field. As electrons hit the argon atoms, they become positively charged, creating a plasma of ionized argon in front of the target of the cathode. The positively charged argon is then accelerated toward the negatively charged target, where they strike the face of the target. After this is completed, the chamber is flooded with a reactive gas, typically nitrogen or oxygen. The gas then combines with the metal atoms from the target and form the desired metal oxide or nitride. This process is advantageous because it allows workers to cover large areas of a surface with a thin film coating.
- Ion Beam Sputtering: This application process is very similar to magnetron sputtering, however, it does differ from the aforementioned process slightly. Ion beam sputtering uses a target of coating and a stream of ions to sputter material from the target. An IBS application method differs from magnetron sputtering in that the IBS process uses an ion gun to direct streams of ions at the target at a 45 degree angle which causes the metal atoms to be knocked off. The sputtered material then deposits itself on the substrates as they are rotated, controlling the thickness of the film. Additionally, in ion beam sputtering, the working gas and reactive gas are added into the process at the same time, causing metal ions to be sputtered and oxidized simultaneously. Ion beam sputtering is used in applications that require low-loss thin film coatings.
- Plasma Impulse Chemical Vapor Deposition: This application process utilizes a combination of microwave plasma and CVD. In this application process, the coating chamber is the reflector to be coated and is filled with precursors similar to the LPCVD process. Once the chamber is completely filled, a microwave pulse ignites the gasses causing the plasma to decompose the precursor coating materials. This reaction results in the reaction products condensing on the surface of the reflector. This process is repeated until the thin film coating is applied to the surface of the reflector in a uniform layer. The main advantage of this process is that it is highly stable and the thickness of the film can be maintained by controlling the flow of gasses and the number of microwave pulse.
We hope that this short blog series has helped to explain the different processes used to apply thin film coatings and has shown the advantages that each of these processes offer. If you would like to learn more about the services that we offer, or you have a thin film coating job that you need to have completed, contact us today or visit our website. At Newport Thin Film Laboratory, we have the knowledge, tools, and experience to handle a wide variety of thin film coating jobs. Contact us today and let’s get started on your next project.