4DS vs Other ReRAM

How 4DS is different to other ReRAM on the market

Filamentary ReRAM vs 4DS Area Based ReRAM

Most other ReRAM on the market is called filamentary and is different from the 4DS approach in several ways. Filamentary is also based on oxygen or metal ions but in this case a string or filament is formed through the cell. The making or breaking of this filament is what sets or resets the cell in this approach.

This filament formation is concentrated on a very small area in the cell, where the 4DS approach uses the entire cell area. The high concentration in a small area presents long term reliability challenges to filamentary cells and their endurance is compromised as a result. The 4DS approach has a gentler impact on the interface which is why we have demonstrated endurances in the billions.

Second, the filamentary approach generally needs several pulses to form the filament, where the 4DS cell responds instantly to a single shot pulse.

Third, filamentary cells depend on a conductive nanowire that has its own thermal stability concerns. Our cell is area based meaning that the entire cell volume supports the conduction.

And lastly the 4DS write current – being area based – scales with the cell size. Filamentary elements are essentially one, two or more oxygen or metal ‘wires’ through the cell and are independent of cell area, so its write current stays high even with smaller geometries.


Area based, lower current density programming, high endurance

Up to 109 Endurance

Analog characteristics

Persistent – extended data retention for energy savings and system fault tolerance

Long retention and short retention can be integrated on same chip

Extremely fast EPIR one-shot response to programming signal – 4.7ns write, well within DRAM window

Ideal for persistent memory backup for Big Data or AI applications

OTHERS – Filamentary

Filament based, high current density, low endurance for reliable cell

Endurance can be as low as 104

Primarily designed for digital use

Non-Volatile – but requires strong error correction or high energy to create multiple filaments

Iterative programming needed for reliable cell

Used as embedded NOR replacement or CXL-based storage memory

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