Technology
Memristors & ReRAM
Memristor and resistive RAM technologies enabling analog computing, neuromorphic systems, and ultra-dense storage.
5 companies
Explainer
Memristors & ReRAM explained
A memristor is an electronic component whose resistance depends on the current that has passed through it, and it keeps that resistance when power is off. Leon Chua described the idea in 1971. In 2008 researchers at HP Labs published a device they linked to it.
Today the term is used loosely for resistive memory devices, known as ReRAM or RRAM. In a typical cell, an electric field forms or breaks a tiny conductive filament in an insulating oxide, which switches the cell between high and low resistance. Those states store data, and intermediate states can hold analog values.
How it differs from the usual approach
Transistor-based memory stores charge, and flash needs high voltages to write. ReRAM stores a resistance, is small, can be made in the metal layers of a chip and uses low voltage. Because cells can hold many resistance levels, a grid of them can multiply and add by itself, which suits neural networks. The difficulty is variability: cells differ from each other and drift, and their endurance and consistency are weaker than established memory.
Where it is used
- Embedded non-volatile memory in microcontrollers and other chips.
- Research in-memory computing chips for neural network inference.
- Neuromorphic hardware that uses cells as synapses.
- Storage-class memory research for data centers.
- Security uses such as random-number generation and unique device identifiers.
What to watch
- Some foundries offer embedded ReRAM options, which is where it is closest to volume use.
- Device variability and endurance remain the main obstacles for using ReRAM for computation.
- Stand-alone ReRAM and phase-change memory have struggled to compete on cost with DRAM and NAND.
- Research chips have shown ReRAM arrays doing neural network inference, though few have reached the market.
Frequently asked questions
What is a memristor?
It is a component whose resistance depends on past current and is kept without power. The term is now also used for resistive memory (ReRAM) devices.
Are memristors the same as ReRAM?
They are closely related. ReRAM is the memory technology, and many ReRAM devices behave as memristors. Whether every ReRAM device fits Chua's original definition is debated among researchers.
Why are memristors interesting for AI?
A grid of them can perform the multiply-and-add steps of a neural network inside the memory, which saves the energy of moving data. Variability between cells is the main challenge.
- RARAMXEED RAMXEED is a Japanese semiconductor company that makes FeRAM and other specialty memory. FeRAM, or ferroelectric RAM, keeps its data without power like flash but writes faster and tolerates far more rewrite cycles, which suits meters, factory equipment and automotive uses. The company was formerly Fujitsu Semiconductor Memory Solution and took the RAMXEED name in 2025. Its headquarters are in Yokohama. Memory & Storage · Memristors & ReRAM —
- CICrossbar Inc. Crossbar develops resistive RAM, or ReRAM, a type of non-volatile memory that stores data by changing the resistance of a thin material and so keeps it without power. Its design uses a crosspoint array, in which memory cells sit at the intersections of crossing wires and can be stacked in layers. The company aims to supply the technology to chipmakers and system-on-chip developers. It was founded in 2010 as a spin-out of the University of Michigan and is based in Santa Clara, California. Memristors & ReRAM · In-Memory Computing · Memory & Storage —
- MemryX MemryX makes the MX3, an accelerator chip for running trained AI models at the edge, meaning in devices rather than data centres. Its at-memory design places processing elements next to the memory that holds the model weights, which reduces the energy spent moving data, and it uses a dataflow approach where results pass directly between compute units. The company sells an M.2 module carrying four MX3 chips rated at up to 24 TOPS, or trillions of operations per second. MemryX was formed in 2019 at the University of Michigan by professors Wei Lu and Zhengya Zhang and is based in Ann Arbor. Memristors & ReRAM · AI Accelerators $44M Series B (March 2025)
- Weebit Nano Weebit Nano develops resistive RAM, or ReRAM, a non-volatile memory that keeps data without power, and licenses it as intellectual property to chipmakers and foundries, starting with embedded memory inside system-on-chip designs. Its technology traces to research by James Tour at Rice University, and it has worked with France's CEA-Leti since 2016. Licensees include onsemi and Texas Instruments. Founded in Israel in 2015 and based in Hod HaSharon, it trades on the Australian Securities Exchange under WBT. Memristors & ReRAM · In-Memory Computing · Memory & Storage —
- ISIntrinsic Semiconductor Intrinsic Semiconductor Technologies makes resistive RAM, a type of non-volatile memory that keeps its data without power, built from silicon oxide. Because the material is common in chip fabrication, the memory can be added to the same CMOS wafers as microcontrollers and edge processors, avoiding a separate flash chip. The company reported scaling its devices to 50 nm with imec. It was founded in 2017 as a University College London spin-off by Anthony Kenyon and Adnan Mehonic. The record lists ferroelectric memory and Austin, Texas, but sources point to silicon oxide memory and a London base. Memristors & ReRAM · Memory & Storage £7M (2023)