|  |
|
|
|
|
The “Millipede”—More than one thousand tips for future AFM storage
| |
|
 |
|
by P. Vettiger,
M. Despont,
U. Drechsler,
U. Dürig,
W. Häberle,
M. I. Lutwyche,
H. E. Rothuizen,
R. Stutz,
R. Widmer,
and G. K. Binnig |
|
|
|
We report on a new atomic force microscope (AFM)-based data storage concept called the “Millipede” that has a potentially ultrahigh density, terabit capacity, small form factor, and high data rate. Its potential for ultrahigh storage density has been demonstrated by a new thermomechanical local-probe technique to store and read back data in very thin polymer films. With this new technique, 30–40-nm-sized bit indentations of similar pitch size have been made by a single cantilever/tip in a thin (50-nm) polymethylmethacrylate (PMMA) layer, resulting in a data storage density of 400–500 Gb/in.2 High data rates are achieved by parallel operation of large two-dimensional (2D) AFM arrays that have been batch-fabricated by silicon surface-micromachining techniques. The very large scale integration (VLSI) of micro/nanomechanical devices (cantilevers/tips) on a single chip leads to the largest and densest 2D array of 32 × 32 (1024) AFM cantilevers with integrated write/read storage functionality ever built. Time-multiplexed electronics control the write/read storage cycles for parallel operation of the Millipede array chip. Initial areal densities of 100–200 Gb/in.2 have been achieved with the 32 × 32 array chip, which has potential for further improvements. In addition to data storage in polymers or other media, and not excluding magnetics, we envision areas in nanoscale science and technology such as lithography, high-speed/large-scale imaging, molecular and atomic manipulation, and many others in which Millipede may open up new perspectives and opportunities.
| |
|
| |
| | |
|
| |
|
IBM Journal of Research and Development, Volume 44, Issue 3, pp. 323-340 (2000).
| |
|
According to the authors of this highly cited paper, “In the 21st century, the nanometer will very likely play a role similar to the one played by the micrometer in the 20th century. The nanometer scale will presumably pervade the field of data storage.” The authors discuss an atomic force microscope (AFM)-based data storage concept called the “Millipede” that has ultrahigh density, terabit capacity, small form factor, and high data rate. Tiny depressions, created with an AFM tip in a polymer, represent stored data bits that can then be read back by the same tip. This technique is capable of achieving data densities exceeding one terabit per square inch, well beyond the expected limits of magnetic recording. This density is equivalent to that needed for storing the content of 25 DVDs on an area the size of a postage stamp. Although the read-back rate of an individual probe is limited, high data rates can potentially be achieved by employing massive parallelism.
IBM researchers affectionately named the device the Millipede because it has thousands of very fine silicon tips that can produce individual bit patterns on the polymer. In order to represent the stored data, the Millipede uses the tips to create pits, corresponding to bit patterns, that are approximately 10 nanometers wide. Perhaps similar devices will someday be suited for mobile device storage, such as that used in digital cameras, mobile phones, and USB storage sticks.
| |
|
|
|
