Impact of the thermal environment on the analog temporal response of HfOx-based neuromorphic devices

Filamentary adaptive oxide devices based on HfOx are a promising technology for neuromorphic computing applications. The resistance of these devices depends on the concentration of oxygen vacancies in the filament region. A local temperature rise from joule heating plays a significant role in the movement of oxygen ions, making thermal management crucial to reliable performance. In this work, the role of the substrate thermal conductivity on the analog performance was investigated at biologically realistic pulse widths. Au/Ti/HfOx/Au adaptive oxide devices were fabricated on substrates with two orders of magnitude difference in thermal conductivity. A lower thermal conductivity substrate dissipates heat more slowly, resulting in a large initial change in resistance from a single operation pulse, which is detrimental to the desired analog behavior. The results were validated by a COMSOL Multiphysics® model that models the flow of heat in both samples.Filamentary adaptive oxide devices based on HfOx are a promising technology for neuromorphic computing applications. The resistance of these devices depends on the concentration of oxygen vacancies in the filament region. A local temperature rise from joule heating plays a significant role in the movement of oxygen ions, making thermal management crucial to reliable performance. In this work, the role of the substrate thermal conductivity on the analog performance was investigated at biologically realistic pulse widths. Au/Ti/HfOx/Au adaptive oxide devices were fabricated on substrates with two orders of magnitude difference in thermal conductivity. A lower thermal conductivity substrate dissipates heat more slowly, resulting in a large initial change in resistance from a single operation pulse, which is detrimental to the desired analog behavior. The results were validated by a COMSOL Multiphysics® model that models the flow of heat in both samples.