Plasmas are known as the fourth state of matter. Plasmas occur naturally in the form of flames, lightning, astronomical nebulae and interstellar matter like our sun, but man-made plasmas have recently become indispensable for advanced materials processing in many high-tech industries. The microelectronics industry employs plasma-based etching tools to produce the billions of microscopic features in thin films with precisely controlled dimensions that are required in computer chips, and also uses plasmas to synthesize insulators, conductors, diamond thin films, solar cells, and high-temperature superconductors. Plasmas are also used to harden the surfaces of cutting tools and to modify surfaces of plastics so paint will stick to them.
Plasmas are produced by adding energy to a gas. For instance, strong electric fields may be used to accelerate free electrons in a gas. The energetic electrons collide with the gas atoms and molecules, and produce an electrified gas consisting of many different types of ions and energetic neutral atoms/molecules that are highlly reactive. The production of such reactive species at temperatures close to room temperature has opened up a wide spectrum of new possibilities for the formation and manipulation of materials that was previously inaccessible.
Even the simplest plasma processing tool is very complex. The major scientific theme of the research performed in the Laboratory for Plasma Processing of Materials is the characterization and understanding of the processes at the plasma-material interface that control the properties of the material or structure that is ultimately produced. This research requires a variety of equipment, including reactors which can produce the plasmas, instruments that characterize the plasma and the plasma-treated materials, and measurement tools that evaluate the crucial variables that determine the ultimate usefulness of the materials and structures thus produced. Many of these tools are housed in the Laboratory for Plasma Processing of Materials. The plasma studies involve many collaborative efforts with industrial laboratories and universities throughout the world.