Introduction: The V-NAND Paradigm Shift
The emergence of NAND flash memory has enabled a revolutionary change in the way we store and retrieve data. NAND delivers increased density, and big performance gains over conventional spinning Hard Disk Drives (HDDs). NAND makes it possible to store more data in a smaller footprint, with lower power consumption, fueling a radical change in data storage enabling applications spanning all facets of computing.
NAND entered production in the 1970s, but NAND did not really become a viable option for mainstream storage devices like Solid State Drives (SSDs) until it could be mass produced at a reasonable cost. The performance of NAND flash has led to explosive gains in performance for personal computers and laptops, and the small size has enabled new compact designs for phones, tablets, and other mobile devices. NAND flash is also transforming the datacenter with increased performance and lower power consumption, delivering more efficiency, and lowering the total cost of ownership. NAND flash even permeates embedded applications, and is used in a diverse range of everyday items.
Cost has been one of the primary obstacles preventing NAND from completely replacing other forms of data storage. The NAND market has grown quickly as flash has become the go-to solution for computing applications of all varieties, but the overriding goal has been to lower production costs as each generation of NAND progresses. Price reductions are normally accomplished by shrinking the size (lithography) of NAND with each successive generation moving from 50nm technology into the 30nm range.
Shrinking the size of NAND allows more data to be stored in a smaller area, which lowers production costs. Lithography shrinks have resulted in denser NAND, but each successive shrink also results in an accompanying reduction in endurance and reliability, and creates tooling and production complications. These issues mean the traditional two-dimensional (planar) NAND structure is approaching the end of its scalability.
To reach new levels in performance, cost, and density, Samsung developed 3D Vertical NAND flash memory, known simply as V-NAND. V-NAND adds another avenue for capacity increases beyond NAND shrinks by scaling capacity vertically. Samsung V-NAND can also store 3-bits per cell, providing even greater capacity at a lower price point.
Samsung 24-layer V-NAND products are in production, delivering top performance and endurance for extended periods. In Samsung's V-NAND based SSDs, V-NAND coupled with an advanced flash controller provides twice the endurance for write data, requires half the power compared to planer (2D) MLC-based drives, and delivers a 20% increase in write performance.
Process maturity is leading to further innovation, and now Samsung is expanding V-NAND to 32-layers, with a projected capacity of 1TB in a single package by 2017. New SSDs with 32-layer V-NAND are poised to provide breakthroughs in read-heavy applications for PC and enterprise users. Stacking layers of charge trap flash structures increase density and improve performance without the ill effects of cell-to-cell interference.