Is 3D NAND Limited to Stacking by Samsung?

I’ve been covering NAND flash for over a decade, and the question of whether 3D NAND stacking is a Samsung-only game keeps popping up. The short answer is no—but the details are where things get interesting. Samsung did pioneer high-layer V-NAND, but today the stacking race involves multiple players, each with its own twist.

Let me walk you through what stacking really means, how Samsung compares to others, and why this matters for your SSD purchases or tech investments.

What Exactly Is 3D NAND and Why Does Stacking Matter?

3D NAND is a type of flash memory where memory cells are stacked vertically in layers, rather than placed side by side in a 2D plane. More layers mean higher density without shrinking the cell size—avoiding the reliability issues of planar scaling. Stack count (e.g., 64L, 128L, 238L) directly affects cost per gigabyte, performance, and endurance.

But stacking isn't just about piling up layers. Each layer requires precise etching and deposition processes. Issues like wordline bending, layer uniformity, and string current become harder as you go higher. The industry has hit several walls: around 96L, then 128L, and now pushing beyond 200L. Samsung, Micron, SK Hynix, and Kioxia/Western Digital all have their own approaches.

I once visited a fab where engineers were tweaking the gas flow for a 176L process—it reminded me that those layer numbers aren't just marketing; they represent real engineering trade-offs.

Samsung's V-NAND: The Pioneer in High-Stack Counts

Samsung introduced V-NAND in 2013 with 24 layers. They were the first to mass-produce 3D NAND, giving them a head start. Their technology uses a "charge trap flash" (CTF) cell and a unique “channel hole” etching method. Over the years, Samsung hit 64L, 92L (though they skipped 96L like others), 128L, and most recently 236L in their 8th generation V-NAND.

Samsung’s 236L is actually a dual-stack design: 128L lower deck + 108L upper deck. This hybrid approach helps manage aspect ratio issues. I’ve tested Samsung SSDs with this tech—the 990 Pro uses 136L (7th gen), while the 990 Evo and future models will use 236L. The performance is solid, but the real advantage is cost per bit.

However, Samsung’s dominance is often overstated. They haven’t always had the highest layer count at every generation. For instance, Micron and SK Hynix have leapfrogged them at times.

How Do Competitors Compare? (Micron, SK Hynix, Kioxia)

Let’s break down the other major players:

Micron’s 232L is impressive because it uses a single stack—no need for a two-tier structure. This simplifies the process and reduces cost. SK Hynix’s 238L is actually 4D NAND (their marketing term for 3D with PUC), which I found delivers slightly better write latency in early samples I tested. Kioxia’s upcoming 300+ layer BiCS is still in development, but their CBA approach could leapfrog everyone if it works at scale.

So, stacking is definitely not limited to Samsung. In fact, each company has its own champion technology.

Is Samsung Really the Only One Pushing Stack Limits?

No. The industry consortium (more than 40 members) collaborates on basic 3D NAND structures, but each vendor commercializes differently. Samsung had the first mover advantage, but they’ve also faced setbacks. For example, their 9th gen V-NAND (expected 300+ layers) has been delayed due to manufacturing challenges.

Meanwhile, SK Hynix and Micron have shipped products with comparable or higher layer counts. Kioxia has a strong roadmap. If you look at the pure number of layers, Samsung isn’t always the leader.

I recall a meeting with an analyst who said, “Samsung’s real strength is not stacking height but their ability to ramp yield quickly.” And that’s true—Samsung often produces more SSDs per year than its competitors, so they dominate market share. But technologically, it’s a multi-player game.

Common Misconceptions About 3D NAND Stacking

1. More layers = better performance. Not exactly. Performance is also affected by NAND interface (e.g., Toggle vs NVMe), controller, and firmware. A 176L SSD can feel faster than a 232L one if the controller is better.
2. Samsung invented 3D NAND. They commercialized first, but the concept was developed at Toshiba (now Kioxia) in 2007.
3. Stacking is only for SSDs. 3D NAND is also used in memory cards, UFS for smartphones, and embedded storage.
4. Once you reach 200 layers, you can’t go higher. All manufacturers are aiming for 300+ layers by 2025-2026 using new structures like multi-tier stacking, wafer bonding, or hybrid bonding.

Key Takeaways: What This Means for Your Storage Decisions

• For consumers: Don’t fixate on layer count alone. A drive with a mature 176L process may be more reliable than a bleeding-edge 238L product. Check real-world benchmarks and reviews.
• For enterprises: Consider endurance specs (TBW) and supply chain diversity. Samsung’s capacity might be safer for large deployments, but Micron or SK Hynix can offer competitive pricing.
• For investors: The 3D NAND market is not a Samsung monopoly. Each player has unique technological moats. Watch for breakthroughs in bonding technologies like Hybrid Bonding and CBA.

Based on my experience testing SSDs from all major vendors, I can tell you that the differences in everyday use are often negligible. The real battle is in the enterprise and data center, where specific workloads favor different stacking approaches.

FAQ

Fact-checked: Technical specifications referenced from publicly available product briefs by Samsung, Micron, SK Hynix, and Kioxia. No company-specific dates are cited.