Design Article
The evolution of phase-change memory
Greg Atwood
7/26/2010 6:38 PM EDT
The history of phase-change memory
The existence of materials that exhibit a controllable change in phase has been known for many years and has been in use for optical memory applications. Electronic memories based on these materials have recently experienced a resurgence of interest for use as a next-generation NVM for the reasons addressed in the previous section. Pioneering work conducted by Micron and others has moved the technology to the forefront of the memory industry R&D activity with a promise to alter the way NVM is used in memory systems.
The history of phase-change materials can be traced back to work starting in the 1950s by Dr. Stanford Ovshinsky who was researching the properties of a class of glassy materials that exhibited the ability to easily and stably change between two phases. By the late 1960s, he had reported that certain of these materials exhibited a reversible change in both resistively and reflectivity upon a change in phase between an ordered (poly-crystalline) state and a disordered (amorphous) state. It was recognized that this effect could be exploited for both optical memories as well as electronic memories. In a September 28th, 1970 issue of Electronics, Energy Conversion Devices (ECD), a company formed by Dr. Ovshinsky, in collaboration with Intel's Gordon Moore reported the world's first electronic phase-change memory array, a 256-bit semiconductor device.
Nearly 30 years later, Ovonyx, a joint venture between ECD and Tyler Lowery, the former CTO/COO of Micron Technology was formed. In February 2000, Intel and Ovonyx announced collaboration and licensing agreement that spawned the modern age of research and development in PCM. In December of 2000, STMicroelectronics ("ST") and Ovonyx also began a collaboration. By 2003, the three companies had joined forces to accelerate progress on the technology by avoiding duplication in basic, precompetitive R&D and through expanding the research scope. In 2005, ST and Intel agreed to codevelop a 90-nm PCM technology.
In 2008, ST and Intel combined their NOR, NAND (ST's NAND), and PCM business to form a new flash company called Numonyx (now part of Micron). The formation of what was Numonyx further accelerated progress in the development of PCM resulting in the first commercial PCM product at the end of 2008.
In the intervening years since that first significant work in 1970, much progress has been made in semiconductor manufacturing technology, enabling the practical development of PCM for both optical and electronic storage devices. Phase-change materials have been in use for many years for high-volume rewritable CDs and DVDs. With the start of production of phase-change materials for electronic memories by Numonyx and others, PCM begins to deliver on its promise to expand the usage of nonvolatile memory.
Next: The present:
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greenpattern
7/26/2010 10:53 PM EDT
"In 2008, ST and Intel combined their NOR, NAND (ST's NAND), and PCM business to form a new flash company called Micron. The formation of Micron has further accelerated progress in the development of PCM resulting in the first commercial PCM product at the end of 2008."
You mean Numonyx, right?
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unknown multiplier
7/26/2010 11:08 PM EDT
The phase change material interaction with nitride or other materials is nontrivial, especially when current density heating (which moves atoms) is needed to activate the mechanism.
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Volatile Memory
7/27/2010 11:54 AM EDT
Incredible! Mr. Atwood claims that phase-change memory writes at 100 MB/s, yet the datasheet of Numonyx (now Micron) own PCM Omneo chip shows that it writes at less than 1 MB/s. When will the lies stop?
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unknown multiplier
7/27/2010 12:55 PM EDT
Phase change memory really compares unfavorably with spin torque MRAM and ReRAM in performance and compares unfavorably with Flash and ReRAM in cost. So ReRAM (or some call it RRAM) will eat PCM's lunch.
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tipotech
7/27/2010 1:33 PM EDT
Looks very interesting , but from what i see Samsung will beat Micron to the market with PCM.
Samsung has stated it will introduce PCM in Mobile Handset first.
Good Luck Micron
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Volatile Memory
7/27/2010 7:41 PM EDT
Samsung lied. Samsung's press release promised that the introduction in mobile handsets will happen by June 30th. Never happened. No product on the market uses any phase-change memory, for obvious reasons. Samsung and Numonyx have both lied repeatedly about the status of their phase-change programs.
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JAK620
7/27/2010 3:44 PM EDT
Hey you wrote this whole article about the background environment and history of PCM. I would expect that you know about "Micron". Stating that Intel formed Micron in 2008 is the most ridiculous false statement I have ever seen on EETimes
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JAK620
7/27/2010 3:59 PM EDT
"Greg Atwood is a senior fellow at Micron Technology, Inc. He received a M.S. degree in physics from Purdue University in 1979, joining Intel Corporation in the same year. "
And you wrote "In 2008, ST and Intel combined their NOR, NAND (ST's NAND), and PCM business to form a new flash company called Micron."?
Wow. This is supposed to be a professional web site for the industry. and you work for Micron?
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zman_tekinsil
7/27/2010 9:02 PM EDT
Deception continues. Mr Atwood did not joint Numonyx. He was with Numonyx all the time, from inception. Numonyx was joint venture between Intel and Microm, mainly.
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zman_tekinsil
7/27/2010 9:02 PM EDT
Meant Joint Venture between Intel and ST. Sorry!
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patrick.mannion
7/27/2010 11:16 PM EDT
Hey all, let's take it easy on Greg here. This was simply a typo. The article was originally submitted to EETimes shortly before Micron sealed the deal on its purchase of Numonyx. (Yes, Numonyx was formed through a joint venture between ST and Intel in 2008.) In the revised version sent to EETimes shortly after the deal was sealed and right before article posted, a global substitution of 'Micron' for 'Numonyx' had been implemented, which caused the error.
I should have caught it, for sure, but these things happen. I have now fixed it. Thanks for spotting this, guys! Much appreciated, as always.
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Volatile Memory
7/28/2010 1:08 AM EDT
patrick.mannion: Why should we take it easy on Mr. Atwood? He is ruining Micron's reputation. The article, as published, leaves the false impression that Micron will engage in the same phase-change memory scam that Numonyx/STM/Intel have been perpetrating for years. Mr. Atwood managed to fool at least one member of the EETimes team, Mr. Peter Clarke, who after reading Mr. Atwood's outdated article, concluded that "Micron ... has indicated that it intends to back the phase-change memory technology" - clearly an unwarranted conclusion, if the article was submitted prior to the closing of the acquisition!
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patrick.mannion
7/29/2010 4:28 PM EDT
Hi again. The article was originally submitted by Numonyx prior to the finalization of the acquisition. It entered the queue here (we get a lot of submissions). When it came time to post it, the acquistion had closed and we sent the article back for revision, with Micron. The version you see now, is the version Micron sent back to us.
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ahshabazz
7/30/2010 2:44 AM EDT
Our memories dont rely on electronics our memories use dark energy - :}
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photo recovery
7/30/2010 4:35 AM EDT
The technology is indeed a productivity booster, and there are easy solutions to privacy issues. Phase-change memory blends the attributes commonly associated with NOR-type flash memory,
Regards,
Data Recovery Software
http://www.datadoctor.biz
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Helicopter
8/3/2010 1:33 AM EDT
I thought PCM write speed is less than 10MBps...
But if the argument is PCM write speed is 100MBps, then NOR could also be architected to achieve the same.
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unknown multiplier
8/3/2010 4:28 AM EDT
They cannot be doing block writes, only individual cells.
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olearydq
7/10/2012 11:48 AM EDT
Figure 2 appears to contain errors in the "Properties" column. The amorphous phase should exhibit low reflectivity and high resistance The polycrystalline phase should exhibit high reflectivity and low resistance.
The text and caption state this also.
Regards,
Daniel O'Leary
Fort Worth TX.
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