ReRAMRRAM

ReRAM, or resistive RAM, is a non-volatile memory technology that stores information by changing the electrical resistance of a dielectric material in a metal-insulator-metal stack. Data are written by applying a voltage that alters the material’s resistance, typically through the formation or rupture of conductive filaments or by a valence-change mechanism in oxide layers. A low-resistance state and a high-resistance state represent binary data, with read operations performed using a small, non-destructive voltage.

Materials and structures commonly used in ReRAM include metal oxide layers such as hafnium oxide (HfO2), titanium oxide (TiO2), and tantalum oxide (Ta2O5). Devices are often arranged in crossbar arrays, which offer high density, and are paired with selector elements to suppress sneak-path currents in dense integrations.

Performance and potential applications vary by material and design, but ReRAM typically offers fast switching speeds in the nanoseconds, low write energy, and non-volatile data retention. Endurance can range from millions to many billions of cycles depending on the implementation. ReRAM is regarded as a candidate for storage-class memory and embedded non-volatile memory, and its multi-level resistance states make it of interest for neuromorphic computing and other novel computing architectures.

Challenges include variability in switching behavior, device-to-device and cycle-to-cycle drift, and reliability concerns in large arrays. Sneak-path currents and the need for effective selectors complicate dense integration. Integration with standard CMOS processes and manufacturing yield are active areas of development, alongside competition from other next-generation memory technologies.

History and status: Research on resistive RAM began in the 1990s and matured through the 2000s and 2010s. Multiple companies and academic groups have demonstrated prototypes and pilots; as of the mid-2020s, ReRAM remains an emerging technology with commercial interest but limited widespread deployment.