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Edit Comment Close Premium member Presentation Transcript Slide 1: Phase Change Memory(PCM) “No one will need more than 637KB of memory for a personal computer. 640KB ought to be enough for anybody,” :Bill Gates (1981) Jibin George Mathews, 06142, S7 EA, Department of Electronics and Communication History : History Dr. Ovshinsky -1960s He formed his company ECD(Energy conversion devices) Article in 1970 September 28 edition of Electronics magazine by him & Gordon Moore titled “non volatile & reprogrammable ” 2000 – STMicroelectronics & ovonyx What is Phase Change Memory ? ”PCM/PRAM uses the unique behavior of chalcogenide glass, which can be "switched" between two states, crystalline and amorphous, with the application of heat.” Slide 3: Technology to produce high purity thin films Cost Numerous breakthroughs in chalcogenide materials. Scaling - Less material to heat –less energy reqd. Flash memory will soon reach its scaling limit. Why PCM is becoming attractive now ?? A review of memory basics ! : A review of memory basics ! What is a computer memory ? Hard disk ?? No,Its simply a type of storage(permanent) “Out of memory” message on computer indicates RAM. Memory is commonly known as RAM. Two types: volatile & nonvolatile(NVRAM) Volatile : Static & Dynamic Historically RAM and Hard disk were called primary and secondary storages respectively NVRAM also called CMOS RAM on-board semiconductor chip powered by a CMOS battery inside computers that stores information such as the system time and system settings for your computer. Memory basics(contd) : Memory basics(contd) Hierarchy of computer storage Primary, Secondary Tertiary Why we use volatile RAM as primary ? Memory basics(contd) : Memory basics(contd) You turn computer ON CPU derives data from ROM &performs POST Loads BIOS from ROM Loads OS from HDD into RAM Opening applications will load them into RAM.Saving them causes them to be written to the storage device and file deleted from RAM Why does a computer need so many memory systems ? 4 groups Flash memory : Flash memory Non volatile Problems related to flash Nand & Nor flash technologies reaching scaling limit If size of code/data increased by a byte that space has to be doubled It can be written to in bytes only ie can be overwritten only if an entire block is erased. So cant be used for small random writes of processor. So a complement of NVRAM & RAM had to be used. Only good for 100k-1M writes Answer is PCM !! No longer should the code and data be separately stored in NVM and RAM Current NVM : Current NVM Answer is PCM !! PCM to the rescue ! : PCM to the rescue ! Contributes attributes of NOR,NAND & RAM Byte alterable Faster writes Faster execution Non volatile Can store both code and data PCM performance Fast (~50 ns) Low voltage (0.4-2 V) Scaling: good Medium endurance (109-1013) NVM/Flash performance Slow (s-ms) High voltage (10-15 V) Scaling: bad Short endurance (105-106) 1.PCM - Introduction : 1.PCM - Introduction Physical characteristics Chemical formula: GexSbyTez Uses chalcogenide glass Varies between two states: Crystalline – low resistance, represents binary 0 Amorphous – high resistance, represents binary 1 Can switch on the order of nanoseconds 1.PCM uses a reversible structural phase-change (between amorphous phase & crystalline phase) 2.The small volume of active media in each memory cell acts as a fast programmable resistor. 2.PCM-Technology concept : 2.PCM-Technology concept Technology concept(contd) : Technology concept(contd) 3.PCM-Basic structure : 3.PCM-Basic structure 4.PCM-Cell element characteristics : 4.PCM-Cell element characteristics Basic Device Operation 5.PCM-operating principle : 5.PCM-operating principle The PCM cell is programmed by application of a current pulse at a voltage above the switching threshold. PCM devices are programmed by electrically altering the structure (amorphous or crystalline)of a small volume of chalcogenide alloy The programming pulse drives the memory cell into a high or low resistance state(phase transition process), depending on current magnitude. Phase transition process can be completed in as quickly as 5 nanoseconds. Information stored in the cell is read out by measurement of the cell’s resistance. PCM-operating principle(contd) : PCM-operating principle(contd) A simple scalable device: An access transistor and a programmable element (PE) High switching speed (~ns) Read/write endurance: >1012 (Flash: 106) Memory array with NMOS transistors: PE based on a switching resistance Phase-change materials amorphous phase: ‘high’-Ohmic crystalline phase: ‘low’-Ohmic Fast switching between amorphous and crystalline phase Slide 17: . Switching 17 Electric pulses induce Joule heating RESET pulse: - T > Tmelt - Rapid cooling down amorphization SET pulse: - T > Tcryst - Longer pulse crystallization V-I characteristics : V-I characteristics . At low voltages, the device exhibits either a low resistance (~1k) or high resistance (>100k), depending on its programmed state : READ region For a reset device : V >Vth to program The reciprocal slope of I-V curve in the dynamic on state is the series device resistance R-I Characteristics : R-I Characteristics shows the device read resistance resulting from application of the programming current pulse amplitude. low amplitude pulses at voltages less than Vth do not set the device. Once Vth is surpassed, the device switches to the dynamic on state and programmed resistance is dramatically reduced as crystallization of the material is achieved. The slope of the right side of the curve is the device design parameter and can be adjusted to enable a multi‐ state memory cell. About Chalcogenide alloy : About Chalcogenide alloy Two types : Nucleation dominant material & fast growth material Chalcogenide or phase change alloys is a ternary system of Gallium, Antimony and Tellurium. Chemically it is Ge2Sb2Te5. Production Process: Powders for the phase change targets are produced by state‐of –the art alloying through melting of the raw material and subsequent milling. This achieves the defined particle size distribution. Then powders are processed to discs through Hot Isotactic Pressing PCM - Advantages : PCM - Advantages PCM uses a reversible structural phase-change scaled device has been demonstrated Cost/Bit Reduction Small active storage medium Small cell size – small die size Simple manufacturing process – low step count Simple planar device structure Low voltage – single supply Reduced assembly and test costs Highly Scalable Performance improves with scaling Only lithography limited Low voltage operation Multi-state demonstrated PCM Today : PCM Today 2004 :Samsung Prototyped a 512 MB module 2006 :Intel created a mass producible 128 module 2008: Intel discovered 2 additional states effectively doubling the Capacity 2008 End: Intel begins shipping beta version called Alverstone Multilevel recording on optical CDs Challenges : Challenges Challenges include :Management of proximity heating with declining cell space. Increased set/reset resistance and decreased read current/set current margin with scaling. Emerging technologies & PCM : Emerging technologies & PCM Conclusion : Conclusion Near ideal memory qualities Broadens system applications – Embedded, System-On-a-Chip (SOC), other products Highly scalable Risk factors have been identified Time to productize More companies looking forward to OUM That might completely replace FLASH. References : References www.ovonyx.com www.ieee.org http://www.xbitlabs.com/news/memory/display/20050912212649.html http://www.theinquirer.net/default.aspx?article=36841 http://www.tgdaily.com/2008/09/13/bitmicro_rolls_out_155_gig_solid/ http://www.storagesearch.com/semico-art1.html http://www.samsung.com/he/presscenter/pressrelease/pressrelease_20060524_0000257996.asp http://www.intel.com/pressroom/archive/releases/20070530corp.htm Objective analysis pcm white paper August 2009\\ PCM – a 180 nm non volatile memory cell element technology forstand alone and embedded applications – Stefan Lai and Tyler Lowrey Current status of Phase change memory – Stefan Lai Slide 29: THANK YOU !! Slide 30: Any Questions ?! You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
phase change memory jibinmathews Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 1102 Category: Education License: All Rights Reserved Like it (5) Dislike it (0) Added: April 20, 2010 This Presentation is Public Favorites: 1 Presentation Description my seminar presentation in engineering college Comments Posting comment... By: kuriyachan (8 month(s) ago) Thanks........ Saving..... Post Reply Close Saving..... Edit Comment Close By: hanxing (10 month(s) ago) Thank you! Saving..... Post Reply Close Saving..... Edit Comment Close By: knockturn.90 (22 month(s) ago) hii..u hav done a gr8 wrkk...covrs almst evry refered sources...i wud like to knw abt the "quote" by bill gates , tat u have included in the first slide....hop u will reply Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Slide 1: Phase Change Memory(PCM) “No one will need more than 637KB of memory for a personal computer. 640KB ought to be enough for anybody,” :Bill Gates (1981) Jibin George Mathews, 06142, S7 EA, Department of Electronics and Communication History : History Dr. Ovshinsky -1960s He formed his company ECD(Energy conversion devices) Article in 1970 September 28 edition of Electronics magazine by him & Gordon Moore titled “non volatile & reprogrammable ” 2000 – STMicroelectronics & ovonyx What is Phase Change Memory ? ”PCM/PRAM uses the unique behavior of chalcogenide glass, which can be "switched" between two states, crystalline and amorphous, with the application of heat.” Slide 3: Technology to produce high purity thin films Cost Numerous breakthroughs in chalcogenide materials. Scaling - Less material to heat –less energy reqd. Flash memory will soon reach its scaling limit. Why PCM is becoming attractive now ?? A review of memory basics ! : A review of memory basics ! What is a computer memory ? Hard disk ?? No,Its simply a type of storage(permanent) “Out of memory” message on computer indicates RAM. Memory is commonly known as RAM. Two types: volatile & nonvolatile(NVRAM) Volatile : Static & Dynamic Historically RAM and Hard disk were called primary and secondary storages respectively NVRAM also called CMOS RAM on-board semiconductor chip powered by a CMOS battery inside computers that stores information such as the system time and system settings for your computer. Memory basics(contd) : Memory basics(contd) Hierarchy of computer storage Primary, Secondary Tertiary Why we use volatile RAM as primary ? Memory basics(contd) : Memory basics(contd) You turn computer ON CPU derives data from ROM &performs POST Loads BIOS from ROM Loads OS from HDD into RAM Opening applications will load them into RAM.Saving them causes them to be written to the storage device and file deleted from RAM Why does a computer need so many memory systems ? 4 groups Flash memory : Flash memory Non volatile Problems related to flash Nand & Nor flash technologies reaching scaling limit If size of code/data increased by a byte that space has to be doubled It can be written to in bytes only ie can be overwritten only if an entire block is erased. So cant be used for small random writes of processor. So a complement of NVRAM & RAM had to be used. Only good for 100k-1M writes Answer is PCM !! No longer should the code and data be separately stored in NVM and RAM Current NVM : Current NVM Answer is PCM !! PCM to the rescue ! : PCM to the rescue ! Contributes attributes of NOR,NAND & RAM Byte alterable Faster writes Faster execution Non volatile Can store both code and data PCM performance Fast (~50 ns) Low voltage (0.4-2 V) Scaling: good Medium endurance (109-1013) NVM/Flash performance Slow (s-ms) High voltage (10-15 V) Scaling: bad Short endurance (105-106) 1.PCM - Introduction : 1.PCM - Introduction Physical characteristics Chemical formula: GexSbyTez Uses chalcogenide glass Varies between two states: Crystalline – low resistance, represents binary 0 Amorphous – high resistance, represents binary 1 Can switch on the order of nanoseconds 1.PCM uses a reversible structural phase-change (between amorphous phase & crystalline phase) 2.The small volume of active media in each memory cell acts as a fast programmable resistor. 2.PCM-Technology concept : 2.PCM-Technology concept Technology concept(contd) : Technology concept(contd) 3.PCM-Basic structure : 3.PCM-Basic structure 4.PCM-Cell element characteristics : 4.PCM-Cell element characteristics Basic Device Operation 5.PCM-operating principle : 5.PCM-operating principle The PCM cell is programmed by application of a current pulse at a voltage above the switching threshold. PCM devices are programmed by electrically altering the structure (amorphous or crystalline)of a small volume of chalcogenide alloy The programming pulse drives the memory cell into a high or low resistance state(phase transition process), depending on current magnitude. Phase transition process can be completed in as quickly as 5 nanoseconds. Information stored in the cell is read out by measurement of the cell’s resistance. PCM-operating principle(contd) : PCM-operating principle(contd) A simple scalable device: An access transistor and a programmable element (PE) High switching speed (~ns) Read/write endurance: >1012 (Flash: 106) Memory array with NMOS transistors: PE based on a switching resistance Phase-change materials amorphous phase: ‘high’-Ohmic crystalline phase: ‘low’-Ohmic Fast switching between amorphous and crystalline phase Slide 17: . Switching 17 Electric pulses induce Joule heating RESET pulse: - T > Tmelt - Rapid cooling down amorphization SET pulse: - T > Tcryst - Longer pulse crystallization V-I characteristics : V-I characteristics . At low voltages, the device exhibits either a low resistance (~1k) or high resistance (>100k), depending on its programmed state : READ region For a reset device : V >Vth to program The reciprocal slope of I-V curve in the dynamic on state is the series device resistance R-I Characteristics : R-I Characteristics shows the device read resistance resulting from application of the programming current pulse amplitude. low amplitude pulses at voltages less than Vth do not set the device. Once Vth is surpassed, the device switches to the dynamic on state and programmed resistance is dramatically reduced as crystallization of the material is achieved. The slope of the right side of the curve is the device design parameter and can be adjusted to enable a multi‐ state memory cell. About Chalcogenide alloy : About Chalcogenide alloy Two types : Nucleation dominant material & fast growth material Chalcogenide or phase change alloys is a ternary system of Gallium, Antimony and Tellurium. Chemically it is Ge2Sb2Te5. Production Process: Powders for the phase change targets are produced by state‐of –the art alloying through melting of the raw material and subsequent milling. This achieves the defined particle size distribution. Then powders are processed to discs through Hot Isotactic Pressing PCM - Advantages : PCM - Advantages PCM uses a reversible structural phase-change scaled device has been demonstrated Cost/Bit Reduction Small active storage medium Small cell size – small die size Simple manufacturing process – low step count Simple planar device structure Low voltage – single supply Reduced assembly and test costs Highly Scalable Performance improves with scaling Only lithography limited Low voltage operation Multi-state demonstrated PCM Today : PCM Today 2004 :Samsung Prototyped a 512 MB module 2006 :Intel created a mass producible 128 module 2008: Intel discovered 2 additional states effectively doubling the Capacity 2008 End: Intel begins shipping beta version called Alverstone Multilevel recording on optical CDs Challenges : Challenges Challenges include :Management of proximity heating with declining cell space. Increased set/reset resistance and decreased read current/set current margin with scaling. Emerging technologies & PCM : Emerging technologies & PCM Conclusion : Conclusion Near ideal memory qualities Broadens system applications – Embedded, System-On-a-Chip (SOC), other products Highly scalable Risk factors have been identified Time to productize More companies looking forward to OUM That might completely replace FLASH. References : References www.ovonyx.com www.ieee.org http://www.xbitlabs.com/news/memory/display/20050912212649.html http://www.theinquirer.net/default.aspx?article=36841 http://www.tgdaily.com/2008/09/13/bitmicro_rolls_out_155_gig_solid/ http://www.storagesearch.com/semico-art1.html http://www.samsung.com/he/presscenter/pressrelease/pressrelease_20060524_0000257996.asp http://www.intel.com/pressroom/archive/releases/20070530corp.htm Objective analysis pcm white paper August 2009\\ PCM – a 180 nm non volatile memory cell element technology forstand alone and embedded applications – Stefan Lai and Tyler Lowrey Current status of Phase change memory – Stefan Lai Slide 29: THANK YOU !! Slide 30: Any Questions ?!