Resistive Switching and Current Status of $HfO_{2}$-Based RRAM

The integration of embedded non-volatile memory (eNVM)devices in a Si CMOS manufacturing process requires to identifycost-effective process flow strategies and Si CMOS compatiblematerials. Hafnium dioxide (HfO2) is a promising dielectric forfuture Resistive Random-Access Memory (RRAM) applications.Following the “More than Moore” (MtM) approach, the advantageis given by the fact that the back-end-of-line (BEOL) integration ofHfO2-based metal-insulator-metal (MIM) memory cells allows acost-effective realization of embedded RRAMs. However, it stillremains difficult in HfO2-based RRAM to further reduce energydissipation and in addition to increase reliability for system-onchip(SoC) applications. Hence, a detailed understanding of theatomic-scale mechanism and the identification of the materialchanges within the insulator are necessary. To address this issue,RRAM integration aspects were accompanied by fundamentalmaterials research studies. First, non-destructive and in-operandoHard X-ray Photoelectron Spectroscopy (HAXPES) wasperformed to correlate the resistive switching effect with materialsmodifications at the Ti/HfO2 interface. The fundamental materialsresearch insights were then transferred to integrated 1T1R devicesin 4 kbit RRAM test arrays