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Posts Tagged ‘array’

PCM + ReRAM = OUM as XPoint

Thursday, June 22nd, 2017

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…

—E.K.

MEMS Mirrors for LIDAR

Monday, April 24th, 2017

Clever integration of new microelectronic/nanoelectronic technologies will continue to provide increased functionalities for modern products. Light Imaging, Detection, And Ranging (LIDAR) technology uses lasers to see though fog and darkness, and smaller less expensive LIDAR systems are needed for autonomous driving applications now being developed by dozens of major companies around the world. A significant step in the right direction has been taken by the US government’s Lawrence Livermore National Laboratory (LLNL) after working with AMFitzgerald on a MEMS mirror Light-field Directing Array (LDA) prototype.

In-process photo of the Light-field Directing Array (LDA) MEMS prototype designed by Lawrence Livermore National Laboratory. (Source: AMFitzgerald & Assoc.) In-process photo of the Light-field Directing Array (LDA) MEMS prototype designed by Lawrence Livermore National Laboratory. (Source: AMFitzgerald & Assoc.)

For the past several years, AMFitzgerald has been developing the fabrication process for a novel MEMS micro-mirror array designed by Dr. Robert Panas’s research group at LLNL, as shown in this video. The technology has been developed specifically to serve LIDAR, laser communications, and other demanding applications where existing MEMS mirror array technologies are insufficient. The novel design offers exceptional speed and tilt range, with three axes (tip-tilt-piston), feedback control, and 99% fill factor. The technology is available for license from the LLNL Industrial Partnerships Office.

At the upcoming MEMS & Sensors Technical Congress, on May 11, Dr. Carolyn D. White will present a case study on how she developed this complex prototype and leveraged AMFitzgerald’s ecosystem of partners to integrate specialty processes. Dr. Alissa Fitzgerald—founder and principle of AMFitzgerald leading the development of innovative MEMS and sensor solutions for specialty applications—will be giving a keynote address on “Next Generation MEMS Manufacturing” at 9:10am May 17 during The ConFab. Dr. Fitzgerald has unparalleled expertise in how to best design MEMS for different fab lines, and is a speaker not to be missed.

—E.K.


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