Characterizing Optical Thin Films (I)

Physical vapor deposition is the most common technique used to deposit optical thin films for a large variety of applications. This requires the ability to get a solid material into a vapor (gaseous) form, to transport it to a surface onto which the film is to be deposited, and to be able to control the physical and optical properties of the resultant film. Sputtering and evaporation in a vacuum are the prevalent techniques used to get solid materials into a vapor form. Regardless of the deposition technique used, it is necessary in the development of coating equipment and coating processes to have the ability to determine the physical and optical properties of the resultant films. There is a considerable range of equipment available to do this. However, all film Optical thin film manufacturers have to have the ability to measure the performance of finished devices. A recording spectrophotometer is the workhorse instrument to do this. Spectral measurements of single layer coatings and certain multi-layers structures can be used to extract optical properties of the films