The Thin Film and Nanostructure Processing Group has two high-vacuum, electron beam evaporator systems for fabrication of single and multilayer thin film specimens. One system has three independent sources and is used for deposition of single and multilayer thin films of materials ranging from lower melting metals, such as aluminum, silver, and copper, up to refractory metals including ruthenium, iridium, and tungsten. The second system, shown to the right, has two independent sources, each capable of depositing as many as six different materials in a single deposition run. With its two-axis, computer-controlled specimen shutter, it is used for fabrication of combinatorial layered as well as compositionally graded specimens.
Projects within the Material Measurement Laboratory frequently require thin films of metals that serve as substrates, electrical contacts on substrates, or as the material of interest itself. These two deposition systems enable fabrication of films under high vacuum conditions. Films from the three-source deposition system support substantial portions of the Division’s research related to microelectronic interconnects, in situ stress measurements during electrochemical processing, and semiconductor nanowires. Examples include thin films of platinum group alloys deposited into sub-100 nm feature, damascene patterned silicon wafers, which have enabled studies of so-called “seedless” processing of copper interconnects of interest to the microelectronics industry, and metallization of aluminum, titanium, nickel, and other metals used to make electrical contacts to nanowire devices.The two-source deposition system is dedicated to fabrication of combinatorial thin film “array” type specimens containing multiple combinations of film thicknesses and/or materials on a single specimen required for high throughput studies of materials properties. The system has been used to stack layers of elements with different magnetic properties and thicknesses for applications to magnetic storage related research. Today, it is mainly utilized to fabricate combinatorial arrays of low density materials for hydrogen storage applications.