NVMemory2009 Pres

8/7/2019 NVMemory2009 Pres

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NON VOLATILE MEMORY

Diana Baren, Ashton Clark, Ryan Clark


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Roadmap

Flash MemoryPRAM

CMOx

NRAM


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Non-volatile Random Access Memory

Memory that does not loose its

information when powered off

Flash, ROM, PRAM, NRAM,

CMOx

Best known form is Flash memory

but PRAM is the Flash of thenext generation


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How Flash Memory Saves Data


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Phase Change Random Access Memory (PRAM

Numonyx.co


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PRAM Cell

Amorphous (0) Crystalline

Amorphous State (Binary 0Numonyx.co


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PCM Mechanisms

Bin ar y 1

Bi na r y 0

Bi na r y 0

Numonyx.co


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PRAM Advantages

Numonyx.co


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Multilevel PCM Breakthrough

Intel and STMicroelectronic

find two additional partial

crystallization states to

store data

Doubled memory capacity

Technologyreview.com


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Difference between PCM and FLASH

Numonyx.co


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How to Beat Flash?

Transistors cannot be used as selection

devices

Diode-like selection device is needed

The memory cell current has to scale warea

http://www.unitysemi.com/downloads/news/NVMTS_2008_complete.pdf


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Flash Scalability

Flash memory cells have a finite # of read/write cycles

When a SSD reaches its cycle limit it doesnt crash

The drive stops allowing writes and becomes read only

Data can still be accessed

Flash is est. to reach its limit by ~ 20nm

http://en.wikipedia.o rg/wiki/Flash_memorySSD = so lid state drive


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Price of Flash vs. DRAM

Flash is cheaper than DRAM and PRAM?


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CMOx Memory Technology

Why is CMOx cheaper / faster than Flash?

No transistor in memory cell

Smaller 0.5F memory cell size2

Uses less than one mA of write current per cell


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CMOx Memory Technology (cont.)

The MLC utilizes a resistance change element

Conduction across the device is uniform

Uses 4 physical layers of MLC memory

Has 4x the density and 10x the write speed of NAND flash

No new process technology is needed to make CMOx


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Why Multi-level Cell?

SLC has high manufacturing costs

MLC has lower manufacturing costs

MLC provides an analog characteristic

a digital component

http://www.usbcompany.co.uk/wp-content/uploads/2008/04/memory-in-

branded-usb-sticks.gif


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How CMOx Works

Through the application of a high electric

field across the Tunnel Oxide (TO) layer,

the charge buildup in the TO can be

controlled, which leads to a change in

device resistance.

Cross section of CMOx Technology


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The 0.5F Memory Cell2

The F measure permits comparison of memory cell sizes acros2

any process technology

The smaller the F measure, the more memory cells per unit ar2

F measures for major memory technologies:2

DRAM 8F or 6F cell size2 2

SLC NAND Flash 4.5F cell size2

MLC NAND Flash 2.25F cell size2

CMOx = 0.5F 2

F = Feature Size Squared2


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NRAM: Nano-RAM

Nantero

Very Promising

Use of CNTs

Van der Waals Force

d A k?


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How does NRAM work?

C Fl


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Current Flow

V d W l F


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Van de Waals Force

OFF STATE ON STATE

NRAM Fi


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NRAM Figures

NRAM Ti i Di


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NRAM Timing Diagram

Ad t t NRAM


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Advantages to NRAM

Can be made much Replaces DRAM and

denser Flash

Low power needed Leads to Instant on

ComputersRetains memory

without power source Longer battery Life

Faster to Write More Resistant to Wear

Q ti


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Questions

NVMemory2009 Pres

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