18-10-2010, 11:16 AM
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MILLIPEDE
ABSTRACT
"Millipede" is a new (AFM)-based data storage concept 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, 3040-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 400500 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-nMcromachining 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 x 32 (1024) AFM cantilevers with integrated write/read storage functionality ever built. Initial areal densities of 100200 Gb/in.2 have been achieved with the 32 x 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.
INTRODUCTION
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. Within a few years, however, magnetic storage technology will arrive at a stage of its exciting and successful evolution at which fundamental changes are likely to occur when current storage technology hits the superparamagnetic limit.
In any case, an emerging technology being considered as a serious candidate to replace an existing but the technology must offer long-term perspectives. The only available tool known today that is simple and yet provides these very long-term perspectives is a nanometer sharp tip. Such tips are now used in every atomic force microscope (AFM) and scanning tunneling microscope (STM) for imaging and structuring down to the atomic scale.
The objectives of our research activities within the Micro- and Nanomechanics Project at the IBM Zurich Research Laboratory are to explore highly parallel AFM data storage with areal storage densities far beyond the expected superparamagnetic limit (60100 Gb/in.2) and data rates comparable to those of today's magnetic recording. The "Millipede" concept presented here is a new approach for storing data at high speed and with an ultrahigh density. Our current effort is focused on demonstrating the Millipede concept with areal densities up to 500 Gb/in.2 and parallel operation of very large 2D (32 x 32) AFM cantilever arrays with integrated tips and write/read storage functionality.