4DS - Anything but Charting, page-2368

• FUN FACT

_{Interface Switching ReRAM – high density memory for mobile and cloud}

The development of Interface Switching ReRAM, a unique type of Non-Filamentary ReRAM, represents a breakthrough in ReRAM technology and is unique to 4DS.

Developing memory storage that is not reliant upon a filament allows cell currents to scale down in line with cell size enabling the smaller geometries necessary to put more storage on a memory chip creating high density memory.A filament-less switching mechanism can operate with low switching currents, due to much more stable currents, essential for high density gigabyte range memories and the retention of data.

4DS has developed a way of controlling the overall resistance of the memory cells using the diffusion of oxygen atoms across the interface and this mechanism is used to reliably control gigabyte memory intended for large-scale storage.

Importantly, Interface Switching ReRAM does not rely on a destruction mechanism thereby increasing endurance, reliability and functional behaviour.

<sub>Filamentary ReRAM – low density memory for IoT and connected devices

The formation of filaments is the most common approach in ReRAM cell research and development today.Filamentary mechanisms may work well at relatively large cell geometries but pose significant current density, retention, endurance, access and control problems when trying to achieve gigabyte range memories.

Filamentary ReRAM has inherent scaling limitations because cell currents are high and are independent of cell size. High switching currents are needed for long data retention and the large current fluctuations typically observed in filament-based ReRAM.

The potential for scalability to smaller geometries is limited by wire current densities.Furthermore, the create and destruct switching mechanism in filamentary ReRAM results in eventual cell breakdown and poses a number of significant limitations for GB silicon storage.</sub>