Annealing and Characterization of Zinc Doped Niobium Oxide for Neuromorphic Computing Applications

Deposition of niobium dioxide on silicon wafers is a potential post-transistor application for memristors as part of a neuromorphic computing architecture. Since pure niobium dioxide (NbO₂) has a crystallization and insulator to metal transition (IMT) temperature that exceeds the thermal budget of current semiconductor processing techniques, doping NbO₂ to reduce both crystallization and IMT temperatures is essential for it to become usable. Through numerous tube furnace anneals with systematically varied temperatures and times, we show that a 10 percent zinc doped sample lowered the NbO₂ crystallization temperature by an average of 75°C, lowering the temperature range in which crystallization is observed from 825-900°C to 750-825°C, along with a decrease in requisite annealing time. The crystallization patterns were first observed through optical microscope imaging, and confirmed with XPS and Raman Spectroscopy. Preliminary optical reflectivity measurements performed in an ultra-high vacuum system in an effort to measure the IMT will be discussed.