We present new results on the use of ion-implantation for controlling resistive switching in HfO₂-based high-k dielectrics.  Resistive switching is a process by which the resistance of a thin dielectric film is reversibly switched between high and low resistance states by the application of current/voltage pulses, and is of interest for the fabrication of non-volatile memory.  For simple transition metal oxides, such as NiO, this involves the formation of a conductive filament in the dielectric by controlled (soft) breakdown.  Switching is induced by local thermo-chemical fusing (high-resistance -reset) and electric-field –induced reforming (low-resistance -set) of the filament.  In this model, conductive filaments are formed from field-induced defects that accumulate to a percolation threshold during the soft breakdown process.  Thermo-chemical fusing then results from local defect annealing as a result of Joule heating along the filament during the application of a current/voltage pulse.  The filament is reformed across the fused region by the application of a suitable voltage.

The filament forming process and its set/reset response are sensitive functions of film quality, stoichiometry and impurity content, with impurities such as C, known to play a significant role in some cases.  Because ion-implantation can be used to control such parameters it is an ideal tool for studying such effects and for improving non-volatile memory performance.  In this study, we report the forming and switching characteristics of HfO₂-based dielectrics implanted with self-ions and selected impurities, and discuss the results in terms of known dielectric breakdown models.