A new era in flash NAND has begun.
Samsung Electronics said on Monday that it is now mass producing the industry's first 3D Vertical NAND (V-NAND) flash memory, offering a 128 gigabit (Gb) density in a single chip.
According to Samsung, V-NAND breaks away from the floating gate-based planar structure that has been used in conventional memory over the past 40 years. It does this by 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, it's able to provide over twice the scaling of 20nm-class planar NAND flash.
With manufacturing process shrinking down to 10 nm levels and beyond, there has been growing concern about a limit to scalability due to cell-to-cell interference that causes a trade-off in the reliability of NAND flash products. The new V-NAND solves this problem by vertically stacking planar cells, a method that was finally achieved after revamping Samsung's CTF architecture which went into development back in 2006.
"In Samsung’s CTF-based NAND flash architecture, an electric charge is temporarily placed in a holding chamber of the non-conductive layer of flash that is composed of silicon nitride (SiN), instead of using a floating gate to prevent interference between neighboring cells," the company explained. "By making this CTF layer three-dimensional, the reliability and speed of the NAND memory have improved sharply."
Samsung said its vertical interconnect process technology can stack as many as 24 cell layers vertically, using a special etching technology that connects the layers electronically by punching holes from the highest layer to the bottom. Thus by using a vertical structure, higher density NAND products can be achieved by increasing the 3D cell layers without having to continue planar scaling.
Samsung said the 3D V-NAND shows an increase of a minimum of 2X to a maximum 10X higher reliability, and twice the write performance over conventional 10nm-class floating gate NAND flash memory.
"The new 3D V-NAND flash technology is the result of our employees’ years of efforts to push beyond conventional ways of thinking and pursue much more innovative approaches in overcoming limitations in the design of memory semiconductor technology," said Jeong-Hyuk Choi, senior vice president, flash product & technology, Samsung Electronics. "Following the world’s first mass production of 3D Vertical NAND, we will continue to introduce 3D V-NAND products with improved performance and higher density, which will contribute to further growth of the global memory industry."
Nearly ten years of research was dumped into 3D Vertical NAND, the company said, and it now has more than 300 patent-pending 3D memory technologies worldwide. The new 3D V-NAND will be used for a wide range of consumer electronics and enterprise applications, including embedded NAND storage and solid state drives (SSDs).