3D NAND: Making a Vertical String

Toshiba's Original BiCS Diagram - IEDM 2007(The following is an update of a post that originally ran on 1 November 2013.  It was republished in 2024 as a part of a series to honor the 3D NAND inventors who have received the 2024 FMS Lifetime Achievement Award.)


Let’s look at how one form of 3D NAND is manufactured.  For this post we will explore Continue reading “3D NAND: Making a Vertical String”

Why Do Emerging Memories Only Sell into Niches?

Simple box made of four colored triangles labeled MRAM, ReRAM, FRAM, and PCMEvery so often an investor will ask The Memory Guy: “Why does MRAM only sell into niche markets?”

These questions aren’t only about MRAM — some ask about ReRAM, FRAM, or PCM as well.  It’s the same question for all of them.  The answer is pretty simple: They’re expensive.  All of these technologies command prices per gigabyte that are Continue reading “Why Do Emerging Memories Only Sell into Niches?”

What is a 3D NAND?

Applied Materials' Explanation of 3D NAND. A series of diagrams shows: 1) a horizontal NAND string, 2) That string being split into two, 3) The string being folded over at the split, and 4) the folded string being tilted on its end.(The following is an update of a post that originally ran 25 October 2013.  It was republished in 2024 as a part of a series to honor the 3D NAND inventors who have received the 2024 FMS Lifetime Achievement Award.)


In the prior post we discussed the need to go vertically into the body of the die, since NAND flash can not Continue reading “What is a 3D NAND?”

Announcing Our New CXL Report

Sketch of a CXL 3.0 fabric. There are four switches in the middle of the diagram on the top left and right and the bottom left and right. Each switch is connected to all of the others via CXL ISL Links, which are represented by a simple straight line between each one. Each switch is also connected to two hosts through two CXL Links, so there are eight hosts in the sketch. The two right-side switches are also connected to two CXL memory modules, which connect to the CXL link to the switch through a yellow box called "CXL MC" representing the CXL Memory Controller and to a red box marked "Mem" representing the memory chips.The Memory Guy is pleased to announce general availability of a new Objective Analysis Detailed Report: CXL Looks for the Perfect Home.

Since Compute Express Link (CXL) is so important to members of the DRAM market and the hyperscale computing community, the report focuses on those sectors, but it offers Continue reading “Announcing Our New CXL Report”

Why Do We Need 3D NAND?

NAND Flash Capped Gate Structure(The following is an update of a post that originally ran 18 October 2013.  It was republished in 2024 as a part of a series to honor the 3D NAND inventors who have received the 2024 FMS Lifetime Achievement Award.)


A memory chip of a certain area costs about the same amount to produce, no matter how many bits it holds. Naturally, the more bits you can cram onto this chip, the cheaper the price per bit will be. Low cost is of the utmost Continue reading “Why Do We Need 3D NAND?”

FMS – New Focus and a Heavy AI and CXL presence

Last week’s FMS conference, originally the Flash Memory Summit, but now the Future of Memory and Storage, saw a strong return of the show’s original excitement and attendance, with numerous presentations on key new technologies, largely AI and CXL, and crowds similar to those before the pandemic.  FMS is held in early August every year in Santa Clara, California.

The new name is meant to match the show’s content better than Continue reading “FMS – New Focus and a Heavy AI and CXL presence”

What is 3D NAND? Why do we need it? How do they make it?

3D NANDBack in 2013, when Samsung announced its V-NAND, the first production 3D NAND, The Memory Guy blog carried a series of posts to explain the new technology and the reason it was so necessary.

Now that the inventors of this technology have been honored with the FMS Lifetime Achievement Award, I decided that it was time to refresh that series of blog posts.  Once a week for the next nine weeks I will be reissuing a post in this series.  I hope that these will Continue reading “What is 3D NAND? Why do we need it? How do they make it?”

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