Statistical Approach to the RESET Switching of the HfO2-Based Solid Electrolyte Memory

The RESET switching of an oxide-based bipolar solid electrolyte memory with the Cu/HfO2/Pt structure is studied in this work. The parameters of the RESET point defined at the maximum of the RESET current evolution, RESET voltage (V-RESET) and RESET current (I-RESET), are analyzed with a statistical method. The experimental raw data show a U-shape relation between VRESET and the ON-state resistance (R-ON). After data correction by a series resistance (R-S), VRESET is roughly constant and the RESET current (I-RESET) is inversely proportional to R-ON. These behaviors are in agreement with the thermal dissolution model of RESET. The further statistical analyses in terms of Weibull distributions show that the R-ON distribution has a strong influence on the I-RESET and V-RESET distributions. By using a "resistance screening" method, the I-RESET and V-RESET distributions are found to be compatible with a Weibull model. The Weibull slopes of the I-RESET and V-RESET are independent on R-ON, indicating that the RESET point corresponds to the initial phase of CF dissolution, according to our cell-based RESET model for the unipolar VCM (valence change mechanism) device. On the other hand, the scale factor of the VRESET distribution (V-RESET63%) is roughly constant, while the scale factor of the I-RESET (I-RESET63%) is inversely proportional to RON, which is consistent with the thermal dissolution model of RESET and our cell-based RESET model. The RESET switching of the studied oxide-based bipolar solid electrolyte memory is dominated by the thermal dissolution mechanism.