System diagnostics for high-vacuum facility

Abstract

Sputtering remains to be one of the most widely-used method in thin film fabrication of different classes of materials like superconductors, semiconductors, metals, and ceramics. The method involves the bombardment of a material (target) by accelerated inert gas ions (usually Ar⁺ ions), resulting in the release of target atoms, which are then collected on the substrate. A DC or RF field produces a plasma arc which is responsible for ionizing and accelerating the argon gas. Magnetic field was introduced in order to enhance the focus and improve the current density of the plasma. RF magnetron sputtering offers the advantage of allowing the deposition of dielectrics. The sputtering method relies, to a great extent, on a well-designed vacuum system capable of attaining a very low ultimate pressure and allowing easy monitor and control of growth parameters like pressure, temperature, deposition rate, substrate-to-target separation, etc. While a complete system is commercially available from foreign suppliers, the prohibitive cost and the inherent dependence on parts and components not readily available are reason enough to consider other alternatives such as local design and fabrication of one's own system. Though this entails great risks and enormous work, the technical knowledge derived from direct exposure to the rigors of vacuum technology (which is often taken for granted) is a worthwhile prize considering the vast applications of vacuum principles in almost all fields. It was one aim of this study to apply the current technology and known physical principles to fabricate a suitable high-vacuum facility for the preparation of various types of materials in thin film form such as superconductors, metals, semiconductors, and metal oxides and nitrides. Moreover, another important feature of this facility is the evaporation set-up that will complement the sputtering set-up in thin film deposition. Also a physical vapor deposition (PVD) process by itself, thermal evaporation refers to heating a material up to its vapor phase temperature through resistive means and collecting the material vapor on a substrate. Aside from its familiar application in optical coating processes, thermal evaporation offers an alternative and a complement to sputtering in further studies in metallization and dielectric deposition processes with particular applications in IC technology.