Engineering an RF antenna for use in Transparent Conducting Oxide deposition

Summary form only given. Transparent Conducting Oxides (TCOs) are a class of materials that are playing a larger and larger role in society today due to their use in digital displays and touch-screen devices. TCOs are critical in such electronic devices because they have the electrical conductivity necessary for connecting the required circuitry while still allowing light to pass through. A drawback of typical TCO deposition methods is that they require elevated temperatures, either during the actual deposition or during a post-deposition anneal. These elevated temperatures, greater than 100 degrees Celsius, limit the type of substrates which can be deposited upon, such as thin flexible plastic rolls. An alternative to high-temperature deposition or post-anneal has been found by implementation of a secondary RF plasma at 13.56 MHz which can provide directed energy for TCO crystal formation without significant heating of the substrate. The RF plasma allows for an adjustable method of changing the TCO material properties by varying the RF power. When the RF antenna configuration was adapted from a laboratory-scale deposition system to a larger commercial tool, difficulties arose with arcing due to the higher required powers and the higher deposition rate of conducting coatings. These antenna difficulties prevented the implementation of the secondary RF plasma and therefore limited the ability to have superior-quality TCO deposition at low temperatures. A new RF antenna configuration was designed in order to provide the required directed energy while being able to operate in an environment with high deposition rates of conducting films. This presentation will show a quantitative study of both the characteristics of the new RF antenna configuration as well as the beneficial effects of the secondary RF plasma during TCO deposition in a DC magnetron sputtering system.