The "millipede" - nanotechnology entering data storage

Abstract

We present a new scanning-probe-based data-storage concept called the "millipede" that combines ultrahigh density, terabit capacity, small form factor, and high data rate. Ultrahigh storage density has been demonstrated by a new thermomechanical local-probe technique to store, read back, and erase data in very thin polymer films. With this new technique, nanometer-sized bit indentations and pitch sizes have been made by a single cantilever/tip into thin polymer layers, resulting in a data storage densities of up to 1 Tb/in 2 . High data rates are achieved by parallel operation of large two-dimensional (2-D) atomic force microscope (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 2-D array of 32 32 (1024) AFM cantilevers with integrated write/read/erase storage functionality ever built. Time-multiplexed electronics control the functional 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. A complete prototype system demonstrating the basic millipede functions has been built, and an integrated five-axis scanner device used in this prototype is described in detail. For millipede storage applications the polymer medium plays a crucial role. Based on a systematic study of different polymers with varying glass-transition temperatures, the underlying physical mechanism of bit writing has been identified, allowing the correlation of polymer properties with millipede-relevant parameters. In addition, a novel erase mechanism has been established that exploits the metastable nature of written bits.Index Terms-Atomic force microscope (AFM) array chips, microscanner, millipede, nano-indentation, polymer films, scanning probe data storage, thermomechanical write/read/erase.

Experimental study of aerodynamic damping in arrays of vibrating cantilevers

“…Fewer studies have focused on the hydrodynamic interaction of multiple beams vibrating in close proximity. Cantilever arrays are encountered in applications such as the IBM millipede (Vettiger et al 2002) and when mimicking the beating wings of insects (Lehmann et al 2005). Hosaka and Itao (2002) investigated the interaction between two cantilevers oriented such that the lengthwise-edges came in contact when the gap was zero, an orientation which will be referred to in this paper as "edge-to-edge."…”

A New Data Allocation Method for Parallel Probe-Based Storage Devices

“…If is the sector number, the sector is allocated in data allocation round and in position of the corresponding column of , which is given by (10) The first field to store symbols of each codeword of sector is (11) whereas the first field to store symbols of each codeword of sector is given by (12)…”

“…However, the data rates that can be achieved by a single AFM probe are not competitive with current magnetic-recording technologies. One solution to achieve a higher total data rate is the use of arrays of probes operating in parallel [11]. In this case, each probe performs read/write/erase operations on a dedicated area, named a storage or data field, while the storage medium is placed in the -plane.…”

Scanning probe arrays for life sciences and nanobiology applications

“…However, its slow scan speed considerably limits the throughput. It has been shown that this can be overcome by parallel operation of large probe arrays [1,2]. Integrated functionality such as the nanometer scale detection of cantilever deflection will greatly simplify the operation of large 2D probes.…”