Tag Archives: history

PCM + ReRAM = OUM as XPoint

The good people at TECHINSIGHTS have reverse-engineered an Intel “Optane” SSD to cross-section the XPoint cells within (http://www.eetimes.com/author.asp?section_id=36&doc_id=1331865&), so we have confirmation that the devices use chalcogenide glasses for both the switching layer and the selector diode. That the latter is labeled “OTS” (for Ovonic Threshold Switch) explains the confusion over the last year as to whether this device is a Phase-Change Memory (PCM) or Resistive Random Access Memory (ReRAM)…it seems to be the special variant of ReRAM using PCM material that has been branded Ovonic Unified Memory or “OUM” (https://www.researchgate.net/publication/260107322_Programming_Speed_in_Ovonic_Unified_Memory).

As a reminder, cross-bar ReRAM devices function by voltage-driven pulses creating resistance changes in some material. The cross-bars allow for reading and writing all the bits in a word-string in a manner similar to Flash arrays.

In complete contrast, Phase Change Memory (PCM) cells—as per the name—rely upon the change between crystalline and amorphous material phases to alter resistance. The standard way to change phases is with thermal energy from an integrated set of heater elements. The standard PCM architecture also requires one transistor for each memory cell in a manner similar to DRAM arrays.

Then we have the OUM variant of PCM as previously branded by Energy Conversion Devices (ECD) and affiliated shell-campanies founded by tap-dancer-extraordinaire Stanford Ovshinsky (https://en.wikipedia.org/wiki/Stanford_R._Ovshinsky). So-called “Ovonic” PCM cells see phase-changes driven by voltage pulses without separate heater elements, such that from a circuit architecture perspective they are cross-bar ReRAMs.

Ovshinsky et al. successfully sold this technology to industry many times. In 2000, it was licensed to STMicroelectronics. Also in 2000, it was used to launch Ovonyx with Intel investment (http://www.eetimes.com/document.asp?doc_id=1176621), at which time Intel said the technology would take a long time to commercialize. In 2005 Intel re-invested (http://www.businesswire.com/news/home/20051019005145/en/Ovonyx-Receives-Additional-Investment-Intel-Capital). Finally in 2009, Intel and Numonyx showed a functional 64Mb XPoint test chip at IEDM (http://www.eetimes.com/document.asp?doc_id=1176621).

In 2007, Ovonxyx licensed it to Hynix (http://www.eetimes.com/document.asp?doc_id=1167173), and Qimonda (https://www.design-reuse.com/news/15022/ovonyx-qimonda-sign-technology-licensing-agreement-phase-change-memory.html), and others. All of those license obligations were absorbed by Micron when acquiring Ovonyx (https://seekingalpha.com/article/3774746-micron-tainted-love). ECD is still in bankruptcy (http://www.kccllc.net/ecd/document/list/3153).

So, years of R&D and JVs are behind the XPoint Optane(TM) SSDs. They are cross-bar architecture ReRAM arrays of PCM materials, and had the term not been ruined by 17-years of over-promising and under-delivering they would likely have been called OUM chips. Many others tried and failed, but Intel/Micron finally figured out how to make commercial gigabit-scale cross-bar NVMs using OUM arrays. Now they just have to yield the profits…


Andy Grove blessed us all

andrew-grove_1-150x150Andy Grove, the man who codified the commercial IC industry dynamic as “Only the Paranoid Survive” died yesterday at the age of 79. His instinctive paranoia derived from his tragic experiences while growing up in Hungary, as referenced by Wikipedia in the prolog to “Swimming Across: a Memoir”:

By the time I was twenty, I had lived through a Hungarian Fascist dictatorship, German military occupation, the Nazis’ “Final Solution,” the siege of Budapest by the Soviet Red Army, a period of chaotic democracy in the years immediately after the war, a variety of repressive Communist regimes, and a popular uprising that was put down at gunpoint. . . [where] many young people were killed; countless others were interned. Some two hundred thousand Hungarians escaped to the West. I was one of them.

Grove was responsible for guiding Intel in the 1980s through the amazingly risky yet ultimately wildly successful strategy of abandoning memory chip production as part of a diversified product portfolio to “bet the company” on microprocessors. In the September 1997 issue of Solid State Technology, I wrote an article titled “DRAM fab strategies in Asia” that summarizes why and how US companies like Intel strategically abandoned DRAM production:

In the 1960s, US companies created the IC manufacturing industry and enjoyed virtually unchallenged world dominance through the 1970s. Japanese IC companies, though at first the junior companies in low-margin and foundry partnerships, rose to challenge the more senior US companies in the 1980s. By the latter half of the 1980s, Japan effectively owned the DRAM business and Japan`s outstanding success in IC production can be directly traced to early US manufacturing partnerships. One strategy played out by US companies with portfolios of memory chip designs was outsourcing of DRAM production to Korean companies. In so doing, US companies committed their futures to non-DRAM products such as microprocessors, DSPs, and ASICs.

Few executives have sufficient vision while leading a work-force with sufficient discipline to be able to re-invent a company in such a way. The capital equipment investments needed to create a leading-edge IC fab have always been daunting, and as Intel employee #3 who had led engineering Grove was able to see a way to leverage strategic R&D to ensure that leading-edge IC product functionalities would pull in sufficient demand to keep the fabs full. Not only did the fabs stay full, but the x86 microprocessor profit margins allowed Intel to grow to annual sales of $25 billion by the time he was replaced as CEO by Craig Barrett in 1998.

The San Jose Mercury News and EETimes have published wonderful additional remembrances of his life. Andy Grove blessed our industry by being a living example of engineering excellence and legit leadership.