04-12-2012, 06:09 PM
NANO TECHNOLOGY BASED DATA STORAGE
NANO TECHNOLOGY BASED DATA STORAGE paper presentation.pdf (Size: 192.63 KB / Downloads: 27)
ABSTRACT
Storing data in the storage devices such as Magnetic Tape drives, Hard drives, Floppy drives, Compact-Disc, DRAM, SRAM, FLASH, etc, is important for the information technology world. But as this industry growing on the needs of storing data is increasing tremendously. We require high data capacity, high data transfer rates. Current trend storage devices can not meet this requirement. In this medley Nanotechnology is useful to design high data compression storage devices with higher data rates. In this regard Ultrahigh storage densities of up to 1 Tb/in2. or more can be achieved by using local-probes techniques to write, read back, and erase data in very thin polymer films. The thermomechanical scaning-probe-based data-storage concept, internally dubbed “millipede”, combines ultrahigh density,, and high data rates. High data rates are achieved by parallel operation of large 2D arrays with thousands micro/nanomechanical cantilevers/tips that can be batch-fabricated by silicon surface-micromachining techniques. The inherent parallelism, the ultrahigh areal densities and the small form factor may open up new perspectives and opportunities for application in areas beyond those envisaged today.
NANO-TECHNOLOGY
The construction of materials whose physical constraints such as length, area, volume rang from 1nm to 100nm. The properties of materials such as physical, chemical, etc,. at this scale are different from at usual scale.
A physicist Richard P. Feynman in December 1959 introduced this concept and he said that "There's Plenty of Room at the Bottom - An Invitation to Enter a New Field of Physics." He notified the possibility of construction of a structure by atom-by-atom from individual atoms which are precisely joined by chemical forces. Finally this led to the a robotic device at nanoscale dimensions that could automatically assemble atoms to create molecules of the desired chemical compounds based on the new concept “universal assembler”. For instance diamond can be formed from such a robot from basic carbon atoms with low cost and large size, light weight, highly hard.
NANOTECHNOLOGY APPLIED TO STORE DATA
Silicon-based semiconductor memory chips and magnetic hard drives have been dominating the data-storage market and they have their limitations as magnetic data storage can not exceed the areal density 250 Gbit/in2. At the same time DRAM, SRAM, FLASH Memory chips having the limitations no of Transistors per chip and difficulties in decreasing feature size(2λ). These limitations can be overcome through the new innovative technology namely NANO TECHNOLOGY. Applying nanotechnology to data storage will result in memory devices with high capacity of aeral density of 1 TeraByte/square inch. Techniques that use nanometer-sharp tips for imaging and investigating the structure of materials down to the atomic scale, such as the atomic force (AFM) is suitable for the development of ultrahigh-density storage devices. As the simple tip is a very reliable tool for the ultimate local confinement of interaction, tip-based storage techno-logies can be regarded as natural
candidates for extending the physical limits that are being approached by conventional magnetic and semiconductor storage.
NANO-TIP
A sharp pointer type object having nano dimensions is a nano-tip are cantilever. Several of such tipscalled probe and large no.of such probes is used to write and read back data using thermomechanical method on a thin polymer film. The thermomechanical probe-based data-storage concept, millipede_, combines ultrahigh density, small form factor, and high data rates by means of highly parallel operation of a large number of probes. This device stores digital information in a completely different way from magnetic hard disks, optical disks, and transistor-based memory chips. The ultimate locality is provided by a tip, and high data rates result from the massively parallel operation of such tips.
PRINCIPLES OF OPERATION
In cantilever-array storage technique Information is stored as sequences of inden-tations. The presence and absence of indentations will also be referred to as logical marks. Each cantilever performs write/read/ erase operations within an individual storage field with an area on the order of 100%100 μm2. Write/read operations depend on a mechanical x/y scanning of either the entire cantilever array chip or the storage medium. The tip-medium spacing can be either controlled globally by a single z-actuation system for the entire array, or by simply assembling the device with a well-controlled z-position of the components such that the z-position of each tip falls within a predetermined range.
Efficient parallel operations of large 2D arrays can be achieved by a row/column time-multiplexed addressing scheme similar to that implemented in DRAMs. In our device, the multiplexing scheme could be used to address the array column by column with full parallel write/read operation within one column. The time between two pulses being applied to the cantilevers of the same column corresponds to the time it takes for a cantilever to move from one logical-mark position to the next. An alternative approach is to access all or a subset of the cantilevers simultaneously without resorting to the row/column multiplexing scheme. Clearly, the latter solution yields higher data rates, whereas the former leads to a lower implementation complexity of the electronics.
WRITING AND READING OF DATA
Thermomechanical writing is achieved by applying a local force through the cantilever/tip to the polymer layer and simultaneously softening the polymer layer by local heating. The tip is heated by application of a current pulse to a resistive heater integrated in the cantilever directly above the tip. Initially, the heat transfer from the tip to the polymer through the small contact area is very poor, but it improves as the contact area increases. This means that the tip must be heated to a relatively high temperature of about 400ºC to initiate softening.