Effect of VOx interlayer in Cu /HfOx/TiN cell and its resistive switching mechanism

In order to improve the performance of HfO_x-based resistive random access memory (RRAM), a VO_x buffer layer was introduced in the Cu/HfO_x interface of Cu/HfO_x/TiN RRAM cell in this paper. Their resistive switching characteristics (such as I-V characteristics, endurance and retention) and the switching mechanism were investigated. Results show that the VO_x buffer layer acts as a barrier which avoids excessive Cu ion reaching to HfO_x layer as result to improve the device performances. The current conduction mechanism of low resistive state (LRS) is Ohmic conduction while the high resistive state (HRS) is Schottky emission. Based on the negative temperature coefficient of LRS resistance and conduction mechanism, we believe that the resistive switching between HRS and LRS is attributed to the Cu-CF´s formation and rupture.