Kioxia announced that it has developed a new semi-circular 3D storage unit structure called Twin BiCS FLASH. This semi-circular 3D floating grid unit structure, pioneered by Kioxia, has a larger programming/erasing window and slope, and the cell size is smaller than the traditional circular design of the charge trap unit. Looking ahead, this design promises to play a huge role in storage appliances beyond 4-bit (QLC) — reducing the number of stack layers or providing higher storage density.
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The new technology was announced at the IEEE International Electronics Conference in San Francisco earlier this month. In recent years, as the number of 3D stacking layers has increased, manufacturers have been able to achieve higher bit density at a lower cost.
However, after more than 100 layers, the complexity of the process increases rapidly, presenting greater challenges to product quality and consistency. To overcome these problems, Kioxia proposed a new semi-circular unit design.
On the basis of the traditional circular unit, the gate electrode is split, thus reducing the size of the unit, in order to achieve high density storage in the case of fewer unit layers.
The semi-circular float (FG) unit has excellent programming/rewritability and is expected to achieve a tight QLC Vt distribution and smaller cell sizes, according to Kioxia.
As a viable option for the industry to move forward in pursuit of higher bit density, the company will continue to work on and put into practical application seeking twin BiCS FLASH.