This system has been associated with high endurance demonstration (trillion cycles), but products are specified at 100K cycles. Filament diameters as large as ~100 nm have been observed. Panasonic released a 4Mb part with Fujitsu, and is developing 40 nm embedded memory with UMC. HP memristor On 30 April 2008, HP announced that they had discovered the memristor, originally envisioned as a missing 4th fundamental circuit element by Chua in 1971. On 8 July they announced they would begin prototyping ReRAM using their memristors. HP first demonstrated its memristor using TiOx, but later migrated to TaOx, possibly due to improved stability. The TaOx-based device has some material similarity to Panasonic's ReRAM, but the operation characteristics are different. The Hf/HfOx system was similarly studied. Adesto Technologies The Adesto Technologies ReRAM is based on filaments generated from the electrode metal rather than oxygen vacancies. The original material system was Ag/GeS2 but eventually migrated to ZrTe/Al2O3. The tellurium filament achieved better stability as compared to silver. Adesto has targeted the ultralow power memory for Internet-of-Things (IoT) applications. Adesto has released products manufactured at Altis foundry and entered into a 45 nm foundry agreement with TowerJazz/Panasonic. Weebit Nano Weebit Nano has been working with CEA-Leti, one of the largest nanotechnology research institutes in Europe to further ReRAM technology. Beginning in November, 2017, the company has demonstrated the manufacturability in 40 nm SiOx ReRAM cells, followed by demonstrations of working arrays in 2018 and discrete components in 2020. In July 2021, the company taped out its first embedded ReRAM modules. In September 2021, Weebit, together with Leti, produced, tested and characterized a 1 Mb ReRAM array, using a 28 nm FDSOI process on 300mm wafers. Crossbar Crossbar implements an Ag filament in amorphous Si along with a threshold switching system to achieve a diode+ReRAM. Their system includes the use of a transistor in 1T1R or 1TNR architecture. Crossbar started producing samples at SMIC on the 40 nm process in 2017. The Ag filament diameter has been visualized on the scale of tens of nanometers. Programmable metallization cell Infineon Technologies calls it conductive-bridging RAM(CBRAM), NEC has a variant called "Nanobridge" and Sony calls their version "electrolytic memory". New research suggests CBRAM can be 3D printed. Quantum dot resistive memory device Quantum dot based non-volatile resistive memory device with a switching speed of 10 ns and ON/OFF ratio of 10 000. The device showed excellent endurance characteristics