Forming-Free HfO_x-Based Resistive Memory With Improved Uniformity Achieved by the Thermal Annealing-Induced Self-Doping of Ge

In this work, a forming-free HfOx-based resistive random access memory (RRAM) with improved uniformity is successfully demonstrated without an additional doping process, ionic injection, or special layer deposition. The significantly enhanced performances can be attributed to the self-doping of Ge atoms from the Ge bottom electrode (BE) into the HfO2 layer during the postdeposition annealing (PDA) process. Besides, the RRAM provides a lower reset current and a higher ON/OFF ratio than the reported forming-free RRAM. These excellent properties are beneficial to the application of power-saving RRAM and its circuit operation.