Resistance switching in HfO2 metal-insulator-metal devices

Resistance switching is studied in Au/HfO2 (10 nm)/(Pt, TiN) devices, where HfO2 is deposited by atomic layer deposition. The study is performed using different bias modes, i.e., a sweeping, a quasistatic and a static (constant voltage stress) mode. Instabilities are reported in several circumstances (change in bias polarity, modification of the bottom electrode, and increase in temperature). The constant voltage stress mode allows extracting parameters related to the switching kinetics. This mode also reveals random fluctuations between the ON and OFF states. The dynamics of resistance switching is discussed along a filamentary model which implies oxygen vacancies diffusion. The rf properties of the ON and OFF states are also presented (impedance spectroscopy).