12-04-2011, 02:44 PM
PRESENTED BY
PRABIN KUMAR SATAPATHY
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INTRODUCTION
• N-RAM: A computer memory technology
• Developed by: NANETRO & NANOMOTORS
• It is nonvolatile RAM, based on the mechanical position of carbon nanotubes deposited on a chip-like substrate.
Memory with actual moving parts, with dimensions measured in nanometers.
NANOTUBES
• Conductors of electricity.
• Very small in size
• Cylindrical, with at least one end typically capped with a hemisphere of the Bucky ball structure.
• Two types of nanotubes:
1. single-walled nanotubes (SWNTs)
multi-walled nanotubes (MWNTs).
STRUCTURE OF N-RAM
• It has 3 layers i.e.-
1. silicon layer,
2. transistor layer
3. supporting layer
• NRAMs are built by depositing masses of nanotubes on a pre-fabricated chip.
• Gold terminals are deposited on top.
Interconnectors are used to connects the electrodes
• Nano anodes are the main conductors of electricity.
• Any number of methods can be used to select a single cell for writing.
• Selected cells will have a high voltage to cause the flip.
WORKING PRINCIPLE
• Each NRAM "cell" consists of a number of nanotubes suspended on insulating "lands" over a metal electrode.
• Works on the Van der walls force of interaction to create basic on/off junctions of a bit.
• Two nanotubes are perpendicular to each other one is positive and other negative, they will bend together and touch.
Small voltage No current flow (“off” state)
High voltage nanotubes attract(“on” state)
• The chip will stay in the same state until you make another change in the electric field.
• So when you turn the computer off, it doesn't erase the memory.
• We can keep all the data in the NRAM and gives the computer an instant boot.
ADVANTAGES
• High density (~100T/cm2), thus more storage area.
• Memory is retained even after the power is removed.
• Low energy consumption
• Flash memory are having a lifetime of 10,000 to 100,000 writes. But NRAM avoids this problem as it uses “low energy” for both read & write.
• Provides better performance than DRAM.
• Takes very less space, hence can replace CPU cache.
• High speed (~100GHZ)
• Low cost
DIFFICULTIES
• RAM structure is hard to be assembled.
• It is nonvolatile.
• Input energy has to be controlled very carefully.