Toshiba And Western Digital Readying 128-layer 3D NAND Flash Fix

Toshiba and Western Digital Readying 128-layer 3D NAND Flash: A New Milestone for SSDs

SSDs are the preferred storage devices for many applications, thanks to their fast performance, low power consumption and high reliability. SSDs rely on NAND flash memory, which stores data by changing the electrical charge of cells. The more cells a NAND flash chip can fit in a given area, the higher its capacity and the lower its cost per gigabyte.

One way to increase the cell density of NAND flash memory is to stack multiple layers of cells vertically, creating a 3D structure. This allows more cells to fit in the same die area, without shrinking the cell size and compromising the performance and endurance. The number of layers in a 3D NAND flash chip is one of the main indicators of its technological advancement and competitiveness.

Currently, most of the NAND flash manufacturers are producing 96-layer 3D NAND flash chips, which offer capacities up to 1.33 terabits (Tb) per die for QLC (4 bits per cell) and up to 512 gigabits (Gb) per die for TLC (3 bits per cell). However, two of the leading players in the NAND flash industry, Toshiba and Western Digital, are readying a new generation of 3D NAND flash chips with 128 layers, which will offer capacities up to 1 Tb per die for QLC and up to 512 Gb per die for TLC. These chips will be based on Toshiba's BiCS-5 technology, which uses a circuitry under array (CuA) design that reduces the die size and improves the write speed.

What Are the Benefits of 128-layer 3D NAND Flash?

The main benefits of 128-layer 3D NAND flash are higher density, lower cost and faster performance. Here are some details:

Higher density. By adding 32 more layers to the existing 96-layer design, Toshiba and Western Digital can increase the capacity of their NAND flash chips by about 33%. This means that they can fit more data in the same physical space, or reduce the number of chips needed for a given capacity. For example, a 1 TB SSD that currently requires eight 96-layer QLC chips could be made with four 128-layer QLC chips, saving space and power.

Lower cost. By increasing the capacity of their NAND flash chips, Toshiba and Western Digital can reduce their production costs per gigabyte. This means that they can offer more competitive prices for their SSDs, or increase their profit margins. For example, a 1 TB SSD that currently costs $100 could be reduced to $67 with 128-layer QLC chips, or maintain its price but offer higher performance and endurance.

Faster performance. By using a CuA design, Toshiba and Western Digital can improve the write speed of their NAND flash chips by doubling the number of planes per die. A plane is a section of a die that can be accessed independently by the controller. Having more planes means that more data can be written in parallel, increasing the throughput. For example, a 96-layer TLC chip with two planes can write at 82 MB/s per unit-channel, while a 128-layer TLC chip with four planes can write at 184 MB/s per unit-channel.

What Are the Challenges of 128-layer 3D NAND Flash?

The main challenges of 128-layer 3D NAND flash are technical difficulties, market competition and consumer demand. Here are some details:

Technical difficulties. Developing and manufacturing 128-layer 3D NAND flash chips is not an easy task. It requires high-precision equipment and processes to etch and deposit hundreds of millions of cells in a vertical stack without defects or errors. It also requires sophisticated algorithms and firmware to manage the complex operations and error correction of the cells. Toshiba and Western Digital have been working on this technology for several years, but they still face some risks and uncertainties in terms of yield, quality and reliability.

Market competition. Toshiba and Western Digital are not the only ones working on 128-layer 3D NAND flash chips. Their main rivals, Samsung, SK hynix and Micron, are also developing their own versions of this technology, with different features and specifications. For example, Samsung's sixth-generation V-NAND will have 176 layers and QLC cells with up to

What Are the Implications of 128-layer 3D NAND Flash for SSDs?

The introduction of 128-layer 3D NAND flash chips by Toshiba and Western Digital will have significant implications for the SSD market and the end users. Here are some of them:

Higher capacity SSDs. With 128-layer 3D NAND flash chips, Toshiba and Western Digital will be able to offer SSDs with higher capacities than ever before. For example, a single-sided M.2 2280 SSD that currently has a maximum capacity of 4 TB with 96-layer QLC chips could be increased to 8 TB with 128-layer QLC chips. This will enable more storage space for applications that require large amounts of data, such as video editing, gaming and cloud computing.

Lower cost SSDs. With 128-layer 3D NAND flash chips, Toshiba and Western Digital will be able to lower the cost per gigabyte of their SSDs, making them more affordable for a wider range of users. For example, a 1 TB SATA SSD that currently costs around $100 could be reduced to around $67 with 128-layer QLC chips, making it more accessible for mainstream consumers and budget-conscious users.

Faster performance SSDs. With 128-layer 3D NAND flash chips, Toshiba and Western Digital will be able to improve the performance of their SSDs, especially for write-intensive workloads. For example, a PCIe Gen4 NVMe SSD that currently has a sequential write speed of around 4 GB/s with 96-layer TLC chips could be increased to around 7 GB/s with 128-layer TLC chips. This will enable faster data transfer and processing for applications that require high-speed performance, such as artificial intelligence, machine learning and big data analytics.

When Will We See 128-layer 3D NAND Flash SSDs?

Toshiba and Western Digital have not announced the exact timeline for the commercial production and availability of their 128-layer 3D NAND flash chips and SSDs. However, based on their previous track record and industry trends, we can expect to see them sometime in late 2020 or early 2021. This will coincide with the launch of other next-generation technologies, such as PCIe Gen5 and DDR5, that will further enhance the performance and capacity of SSDs.

Conclusion

Toshiba and Western Digital are readying a new generation of 3D NAND flash chips with 128 layers, which will offer higher density, lower cost and faster performance than their current 96-layer chips. These chips will enable them to offer SSDs with higher capacities, lower prices and faster speeds than ever before. This will benefit the SSD market and the end users who demand more storage space, more affordability and more performance from their storage devices.

Conclusion