Protecting the Electron Playground: Characterizing and Preventing Dielectric Breakdown of Silicon Dioxide (SiO2)

Field Effect Transistors (FET) are vital in computer chips and Condensed Matter Physics. We emphasize the use of the "field effect" to modify the electron carrier density in quantum materials, particularly in graphene – a semi-metal with a single-atom thickness. Instead of using the FET as a transistor, we aim to understand the fundamental electronic properties of graphene in relation to the carrier density. The main goal of my team's project was to study how longitudinal strain affects graphene's electronic properties. The field effect is realized by forming a capacitor between graphene and a gate electrode, separated by a dielectric layer – in this case, silicon dioxide (SiO₂). A challenge encountered is the breakdown of SiO₂ due to oxygen defects, leading to device failure when an excessive voltage is applied across the dielectric. I will describe our approach to developing an automated method to assess the safe operating voltage limits. Using python-based software, we calculated the local slope for data visualization, enabling a more comprehensive understanding of Resistance vs. Voltage (RV) curves. Building upon existing techniques, our method is essential for our group and potentially beneficial for others using similar scripts. Through detecting leakage in SiO₂, we identified and prevented its breakdown, demonstrating that 90 nm silicon wafers can handle up to 70 volts in FET gating. Our research paves the way for a deeper understanding of graphene's impact, fostering advancements in quantum technologies.