Atmospheric neutron irradiation effects on conductance update linearity of Mg:HfO <i>x</i> (9 at. %)-based memristive synapse

Abstract

Studying the atmospheric neutron irradiation effects on memristive synapses is fundamental to extending the application of memristive neuromorphic chips in aviation. However, such studies remain rarely reported. Here, atmospheric neutron irradiation effects on the conductance update linearity of Mg:HfOx (9 at. %) memristive synapses—key to chip computation—were studied, and degradation was analyzed from the perspective of conductive filaments formation/rupture. During long-term depression, the memristive synapse fails to fully return to its original high-resistance state under optimal pulse programming voltage, leading to a reduction in the conductance update linearity. This decrease becomes increasingly pronounced with the increase in atmospheric neutron irradiation fluence. Analysis by x-ray photoelectron spectroscopy and electrochemical impedance spectroscopy reveals that the atmospheric neutron irradiation generates new oxygen vacancies, forming oxygen-vacancy-enriched regions that inhibit conductive filaments rupture, which is the main reason for the decrease in the linearity of conductance update. The research can provide some supports for the development of memristive neuromorphic chips for aviation applications.