NAND flash is emerging as the sort of chip product that creates new end applications. Back in the 1970s and 1980s, the fast pace of scaling DRAM, SRAM and microprocessors led to the introduction of products such as the digital watch, the pocket calculator, the PC and the mobile phone.
Now, with the cost of NAND flash declining by nearly 40 per cent a year, new applications are opening up, particularly in computing. There is even talk of flash-based laptops – something not seen since Psion brought one out in the 1980s.
“Our largest die is now 4Gbit. This year, in the second half, we’ll have 8Gbit on 60nm and, in the first half of 2007 we’ll launch a 16Gbit on 55nm. It’s already working in prototype,” says Richard Walsh, senior memory manager at Samsung, which has a 60 per cent market share in NAND.
“So every 15 months you get double the memory for the same price, and every year you get a 38 per cent price reduction per bit. It opens the door to what you can do. It opens up lots of applications.”
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Spinning NAND wafers at Intel...
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Two of the most complained-about aspects of laptop PCs are too short a battery life and too long a boot-up time. Later this year, hard disks with a flash cache should help to overcome these two bugbears.
The flash cache disks will be sold to coincide with the launch of the gold code version of Microsoft’s new operating system, Vista, planned for the second half of 2006.
“The theory is that the hard disk doesn’t have to run all the time. Flash-based cache can reduce the number of reads to the hard disk and eliminate a lot of writes,” explains Walsh. “Say you’re using Word in an airport and you need to save the document every five minutes, and your laptop goes into sleep mode every five minutes, then the laptop is constantly running and never getting into sleep mode. If you’re constantly saving the document, then it’s best to keep saving it in flash and not use the hard disk.”
Vista has been tailored to cope with hard disks incorporating a flash-based cache referred to as a hybrid disk.
“The hard disk stores data writes in the flash memory that would traditionally be sent directly to the mechanical hard drive. This data is transferred from flash memory to the hard drive opportunistically – when the flash memory is full or when the system activates the hard drive to access or ‘read’ other data,” explains Microsoft’s Mui Luc. “This approach means the hard drive can be kept still for a large percentage of the time, ultimately requiring less power and extending overall system battery life. And since the mechanical hard drive is not working when you are in sleep state with the hybrid hard drive, you have less risk of hardware problems with the hard drive when you’re on the move.”
Estimates suggest hybrid disks will save more than half an hour of laptop battery life. Naturally they will also reduce boot-up time.
“The initial system instructions required on resume from these states are stored in the flash memory – meaning that users will not have to wait for the traditional hard drive to power on and spin up before processing can begin,” adds Luc. Industry estimates are that boot-up time could be reduced to a few seconds.
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Ready for cutting at Micron
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The traditional areas for NAND – hand-held devices such as mobile phones and MP3s – are going to continue to gobble up more and more flash.
Cameras in phones take more memory as the pixel count increases. And the convergence trend can work the other way: “We think the next thing Apple will add to the iPod is a telephone,” says Samsung’s Walsh. “And we think, by 2008, 500 million phones will have MP3.”
In addition to taking on more internal memory, mobile phones are adding more removable storage. “In 2005, 20 per cent of cell phones shipped with a card slot,” says Walsh. “Expect that to rise to 28 per cent in 2006, and 50 per cent within five years. Nokia in 2005 shipped 50 million phones – 25 per cent of its output – with card slots. Some phones with 4Gbyte hard drives will be replaced with 4Gbyte of flash in 2006.”
Some are saying that NAND has such a reach that it could threaten the use of hard disks in laptops. “How long before the notebook has solid-state memory?” asks Steve Appleton, chief executive of Micron Technologies, who suggests, “five or six years”.
“Flash is not going to go into multi-hundred Gigabyte hard drives, but, for professional users who might want to carry around an OS requiring 2 or 3Gbyte and about 5Gbyte of data, the target of a solid-state laptop is much more likely,” says Samsung’s Walsh. “Something in the 8Gbyte or 16Gbyte range is more likely. But they’re not for gamers, or people with video files, who want these big hard drives.”
The $50 paid for 1Gbyte of flash today will be down to $30 next year, and $20 the year after, and in single figures by the end of the decade. But, even at that price, it will still be about 15 times more expensive than hard disk memory is today.
However, an on-the-move professional needing 16Gbyte of storage costing, say, $150 in 2009, would probably be happy to pay the extra cost of flash over hard disk to have a feather-weight laptop with instant-on.
With all this potential demand, flash has become the hottest product in the semiconductor market. In terms of bits shipped, it has tripled in both of the past two years and will do so again if there is enough capacity to make it.
In terms of dollars, Gartner Dataquest estimates that NAND chip sales rose from $1.5bn in 2000 to $10.7bn in 2005 and will grow to $18bn in 2008.
Apple, which relies on NAND flash for its iPod Nano, has pre-paid $1.2bn to secure NAND flash supplies this year. It has paid $500m each to Samsung and the Intel/Micron flash manufacturing joint venture called IM Flash Technologies, and $200m to Hynix.
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Apple's iPod is helping drive NAND sales
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The fact that the iPod Nano sells for $200 with 2Gbyte of flash has given buyers a stick with which to beat flash suppliers down on price.
NAND is a relatively new product to the mass market but has come a long way in a short time. “Only in the past two to three years has NAND flash come into the mass market and last year it went to 90nm ahead of DRAM,” says Samsung’s Walsh. “Now flash is already down to 70nm, and getting down to 60nm, while DRAM is still at 90nm.”
The scaling potential for flash seems to be limited only by the ability to print smaller transistors – and that is set to go to 30nm and below when extreme ultra-violet (EUV) lithography is introduced.
“The leakage problems that affect logic chips don’t affect memory because they’re not doing anything most of the time,” explains Walsh. “You only get leakage with a status change. With memory that doesn’t happen that often. They sit there quietly until they’re needed.”
Suddenly NAND has become very important. It is both the main chip industry process driver, and the catalyst for new electronics industry end products.