Controlling Conductive Filament and Tributyrin Sensing Using an Optimized Porous Iridium Interfacial Layer in Cu/Ir/TiNxOy/TiN

Controlling the copper (Cu) filament using an optimized porous iridium (Ir) interfacial layer thickness ranging from 2 to 20 nm in a Cu/Ir/TiNxOyTiN resistive switching memory device is investigated for the first time. Transmission electron microscopy (TEM) shows a porous Ir layer, and X-ray photoelectron spectroscopy (XPS) is performed to determine the Ir-0,Ir3+/Ir4+ oxidation states, which are responsible for a super-Nernstian pH sensitivity of 125.5 mV pH(-1) as well as a low concentration of 1 x 10(-12) M tributyrin detected using a 40 n m thick Ir in Ir/TiNxOyTiN structure. The 5 nm thick Ir layer in the Cu/Ir/TiNxOyTiN structure shows current-voltage switching characteristics for 3000 consecutive cycles, a stable RESET voltage, a long program/erase (P/E) endurance of >10(9) cycles under a P/E current of 300 mu A at a high speed of 100 ns, and neuromorphic phenomena compared to those of other Ir thicknesses. Cu migration into the TiNxOy oxide-electrolyte is shown by TEM observations. The tributyrin detection ranging from 1 x 10(-12) to 100 x 10(-12) M using a resistive switching memory device paves the way for the early diagnosis of human diseases as well as artificial intelligence applications in the near future.