Samsung today announced it has begun mass producing three-dimensional flash memory that has benefits of higher data density, improved speed and higher reliability. Current planar NAND memory has scaling issues, with a decrease of cell size new technical challenges arise. The 3D V-NAND as Samsung calls it should make flash memory more scalabale again which should result in faster, cheaper and more reliable SSDs.
Samsung’s new V-NAND offers a 16 GB density in a single chip, utilizing the company’s proprietary vertical cell structure based on 3D Charge Trap Flash (CTF) technology and vertical interconnect process technology to link the 3D cell array. By applying both of these technologies, Samsung’s 3D V-NAND is able to provide over twice the scaling of 20nm-class planar NAND flash.
Current NAND suffers from cell-to-cell interference causing a trade-off in the reliability of NAND and leading to added development time and costs. V-NAND should solve such technical challenges.
Samsung’s CFT technology was introduced in 2006 and works by temporarily placing an electric charge in a holding chamber of the non-conductive layer of flash that is composed of silicon nitride , instead of using a floating gate to prevent interference between neighboring cells. Simplified a floating gate sucks up electrons by applying a voltage to it. The electrons then get trapped between two layers and can be released by changing the voltage again. Whether electrons are trapped of not represents a binary 1 or 0.
From what we understand the difference between NAND as we’re used to nd this new Samsung 3D NAND is that the charge trapping layer is an insulator, while a normal floating gate is a conductor. By using this technology the reliability and speed of NAND memory should improve. Samsung reports an increase of a minimum of 2X to a maximum 10X higher reliabilit and twice the write performance over conventional 10nm-class floating gate NAND flash memory.
According to the company it’s able to stack as many as 24 cell layers vertically, using special etching technology that connects the layers electronically by punching holes from the highest layer to the bottom. With the new vertical structure, Samsung clais it can enable higher density NAND flash memory products by increasing the 3D cell layers without having to continue planar scaling, which has become so difficult to achieve.
While for most consumers the technology behind it is fairly complicated the benefits are clear, faster, cheaper and more reliable SSDs…
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