Memcapacitive Characteristics of Metal-Oxide-Semiconductor Capacitor Structures by Compositional Redistribution

The memcapacitive characteristics in metal-oxide-semiconductor (MOS) capacitor structures consisting of reactive electrode (Mo, Al) and hafnium oxide (HfOX) on n-type Si and indium-gallium-zinc-oxide (IGZO) semiconductor were investigated. The capacitance-voltage (C-V) curves exhibited sequentially changing capacitance as repeating the voltage sweeps in an analog fashion. The saturation capacitance was decreased as repeatedly applying +V, while the depletion capacitance was barely changed at repeated -V application. The capacitance-time (C-t) curves disclosed the same tendency of capacitance change. On the other hand, the MOS structure with inert electrode (Pt) did not show the capacitance change. These memcapacitive behaviors were induced by the migration of oxygen ions between reactive electrodes (Mo, Al) and HfOX, modulating the permittivity and effective capacitor area. These results demonstrated the memcapacitive characteristics in MOS structure through voltage-driven oxygen migration, which could be applied to memory, logic, and neuromorphic devices.