Effect of Proton Irradiation Fluence on the Linearity and Symmetry of Conductance Tuning of a HfO_x/TiO_xHeterojunction-Based Memristor

Binary metal oxide memristor-based artificial neural synapses offer the advantages of high-density information storage, high-efficiency computing, low power consumption, and strong antiradiation damage and are therefore promising aerospace electronic devices. However, the unclear damage trends and mechanisms causing nonlinearity and asymmetry during conductance tuning under irradiation have restricted further development. Here, the damage trends and mechanisms caused by proton irradiation in Au/HfOx/TiOx/Ti memristors were studied. Results show that when the fluence of the proton (25 MeV) irradiation increases to 2× 1011 p/cm2, the Au/HfOx/TiOx/Ti memristor cannot return to its original high-resistance state upon conductance reduction, making the conductance tuning less linear and symmetric. X-ray photoelectron spectroscopy (XPS) analysis revealed that the mechanism underlying the decrease in the linearity and symmetry of the conductance tuning is proton irradiation increasing oxygen vacancies in the heterojunction. These results can guide the better design of metal oxide memristive devices suitable for aerospace devices and better modeling of devices with nonideal properties under irradiation.