Thin Film Deposition: Mark Lust
Mark Lust is a first year PhD student at the Department of Electrical and Computer Engineering. Currently, Mark was an undergraduate researcher under the National Science Foundation (NSF) Research Experience for Undergraduates (REU) Program. He has been a member of the RF Microsystems Laboratory since January 2017.
Since joining the group, Mark has been involved in microfabrication at the Nanotech West cleanroom laboratory and measurements at the ElectroScience Lab. Mark uses DC magnetron sputtering to develop a deposition process for high-quality vanadium dioxide (VO2) thin films. VO2 is a phase change material (PCM) with electrical property of a dielectric below its transition temperature and a conductor above that temperature. Mark’s work involves optimization of the thin film deposition process on the wafer. To measure the phase transition, Mark is using a four-point probe, heating stage, and a high-accuracy surface probe thermometer. The four-point probe uses controlled current to determine sheet resistance, which is measured versus the temperature.
Mark said: “This summer, I learned how to manage my own project. I tested hypotheses and developed a system for obtaining and presenting my data. I also discovered the importance of giving attention to the minutiae of my work and the necessity of precise and accurate measurement. Lastly, I gained valuable, hands-on class /microfabrication experience, as well as skills in both solo-work and collaboration.”
These thin films can be used in a wide variety of applications. Its transition occurs at 68°C, which is much closer to room temperature than those of other PCMs. This allows for feasible and simple control of RF circuits. The fast and high-contrast transition means VO2 can be used in solid-state switches, reconfigurable antennas among a few. Its hysteretic properties can be used for memory application.