4DS Memory Limited announced a new type of ReRAM technology for AI processing, bringing high-bandwidth, high-endurance persistent memory for big data and neural net applications. 4DS' Interface Switching based on PCMO (Praseodymium, Calcium, Manganese, Oxygen) ReRAM technology delivers significant advantages over other filamentary ReRAM technologies and is the first company to develop this high-speed, high-endurance, persistent non-volatile technology on an advanced CMOS node. One of the biggest challenges to the AI market is that traditional CPU architectures cannot efficiently handle the massive volumes of data that must be read into the chip, processed, and the results written back out of the chip.

While new chip architectures are bringing the memory in with the compute (Compute in Memory), this approach is limited by the type of memory they can use that can be fast enough and the amount of memory that can be integrated. With these larger models the challenges of compute data backup and recovery has likewise grown. In addition to speed, energy efficiency has also become more increasingly important as AI processing is forecasted to consume 10 times the energy by 2026 compared to 2023, according to the International Energy Agency.

Because 4DS requires no refresh within its persistence window and can be 'refreshed' within the DRAM operating window (' hidden refresh'), it can uniquely deliver an energy efficient high bandwidth and high endurance memory technology for the AI Age. Key features of 4DS' Area-based ReRAM include the following: Area-based, low current density programming, high endurance and scalable with technology node; Highly responsive with extremely fast single-shot write time of 4.7 ns to deliver low energy per bit writing at DRAM speeds; High bandwidth persistent memory for high performance data protection; High endurance memory with up to 109 endurance demonstrated; Dynamic partitioning: High endurance and high retention sectors can be dynamically allocated with data retention from hours to days to months; High scale and density w 20 nm cell to be demonstrated in the fourth quarter of 2024; Simple integration into any advanced CMOS process using standard fab equipment. 4DS has a development agreement with Belgium-based imec - a world leading research and innovation hub in nano electronics and digital technologies - for a 20nm Mb chip with 1.6B elements to be run at imec in 2024.PCMO ReRAM belongs to a class of Interface Switching ReRAM where the switching mechanism is based on the interface characteristics of the cell.

Specifically, the entire interface area is involved in the switching, which is why it is sometimes also called area-based switching. Oxygen ions, which allows conduction through the cell, are moved in and out of the cell by the electric field pulse. When this oxygen is present, the cell conducts and it is said to be SET.

Likewise, when the oxygen is removed, the current path is lost and it is said to be RESET. Because the entire interface area is involved the current density is kept at a minimum which contributes to the high endurance of the cell.