Joint evaluation of performance and environmental impacts of a microfabricated device

Details

Supervisors

Raskin, Jean-Pierre

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil électricien, à finalité spécialisée

Abstract

Given the current climate crisis, it is crucial to rethink how production and consumption are approached, and this consideration applies to the electronics sector as well. An initial study has shown that the extraction and manufacturing processes involved in using gold for the metallic contacts in vanadium dioxide-based devices are the largest contributors to CO2 equivalent emissions. This research aims to evaluate the viability and characterize the use of aluminum as an alternative for these metallic contacts. Vanadium dioxide is a particularly interesting material due to its reversible transition from an insulating to a metallic state at 68°C, which holds promise for numerous applications, including neuromorphic systems. Throughout this thesis, vanadium dioxide resistors are fabricated with aluminum contacts, using gold contacts as a reference. Each fabrication step is thoroughly explained. The devices are characterized using microscopy and Raman spectroscopy to ensure that the VO2 transitions correctly and to extract values for the VO2 sheet resistance as well as contact resistances with the different metals. The study concludes by conducting aging tests to analyze the difference in aging between the two metals and to assess whether aluminum can serve as a sustainable and viable alternative to gold. The findings suggest that aluminum is indeed a potential alternative for these contacts, but significant variability was observed during measurements (both cycle-to-cycle and device-to-device variability). Additionally, a highly resistive first cycle was noted, indicating damage due to Joule heating, followed by a decrease in resistivity in subsequent cycles.