Effects of Cu ion doping in HfO₂-based atomic switching devices

Here, we report an active metal ion doping technique with insertion of active metal layers (Cu) into a solid electrolyte (HfO₂ to improve the performance of the HfO₂-based atomic switches. By applying our doping technique on the HfO₂-based atomic switches, we confirmed that bipolar switching characteristics and device operation stability of the atomic switches were successfully improved. In case of bipolar switching characteristics, the operating voltage decreased from 0.61 V to 0.48 V, and the switching time improved from 7.4 sec to 5.3 sec. However, the on/off-current ratio decreased from 1.90×10⁷ to 1.50×10⁶. In terms of the device operation stability, the cyclic endurance of the atomic switch was enhanced approximately 2-fold (more than 100 cycles) by inserting a thin Cu layer. Based on these findings, we expect our technique to play a crucial role in enhancing the performance of atomic switches.