Earlier this year, Intel and Micron began shipping 3D NAND flash drives with up to 3.5TB of capacity in an M.2 expansion card. Credit: Intel
The NAND flash technology that Toshiba introduced in 1989, making thumb drives, SSDs and your smartphone's memory possible, has finally reached a development dead end.
Toshiba and other major manufacturers of planar floating gate NAND flash are setting those engineering efforts aside and focusing development on 3D NAND, also known as vertical charge trap flash and other 3D memories.
Scott Nelson, vice president in charge of Toshiba's memory business, said planar or 2D NAND flash will continue to be sold because there are still many "lower density" applications for it. But the economics of shrinking it below 15nm don't make sense.
"It's just so challenged to shrink it any further. These are baby steps now," Nelson said. "As of now, there's nothing on the roadmap that would indicate another floating gate generation."
Surprisingly, 2D NAND's development demise is a relatively recent, if not unexpected, event. Jim Handy, principal analyst with semiconductor research firm Objective Analysis, about a year ago said he spoke with An Steegen, the vice president of semiconductor research and development at Imec, "and there was a clear path to 13nm for planar NAND." (Imec is the research consortium for semiconductor companies.)
At Semicon, last month, Steegen changed her tune.
"She said that the NAND makers have dropped that project...and were putting all of their resources into 3D," Handy said. "So, yes, planar ends at 15nm."
Toshiba development partner SanDisk said the same in and interview with Computerworld.
Samsung introduced its vertical TLC NAND or "V-NAND" last year, a 32-layer cell structure based on Charge Trap Flash (CTF) technology and vertical interconnect process technology to link the cell array. By applying the latter technologies, Samsung's 3D V-NAND can provide over twice the scaling compared to its 20nm-class planar NAND flash.
In 2013, Samsung became the first semiconductor manufacturer to begin producing 3D NAND. Its V-NAND chip provides two to 10 times higher reliability and twice the write performance over its planar NAND flash.
Scott DeBoer, vice president of research and development at Micron -- a partner in NAND flash development with Intel -- said their companies' efforts going forward also will also be focused on two new 3D memory technologies.
Intel and Micron are developing a 32-layer 3D NAND flash based on charge trap memory; they also recently announced a resistive RAM (ReRAM) memory called 3D XPoint. The 256Gbit X3 chip, based on the new 3D XPoint technology, increases performance and resilience by up to 1,000 times over planar NAND. Intel said its 3D NAND will also hold 256Gbits (32GB) per chip.
Sign up for Computerworld eNewsletters.