Ultrahigh-density atomic force microscopy data storage with erase capability

Abstract

We report a simple atomic force microscopy-based concept for a hard disk-like data storage technology. Thermomechanical writing by heating a Si cantilever in contact with a spinning polycarbonate disk has already been reported. Here the medium has been replaced with a thin polymer layer on a Si substrate, resulting in significant improvements in storage density. With this new medium, we achieve bit sizes of 10-50 nm, leading to data densities of 500 Gbit/in. 2 . We also demonstrate a novel high-speed and high-resolution thermal readback method, which uses the same Si cantilevers that are used in the writing process, and the capability to erase and rewrite data features repeatedly.

Atomic force microscope cantilevers for combined thermomechanical data writing and reading

“…7. Binnig et al 5 demonstrated a data density of 400 Gb/in. 2 by writing thermomechanical data bits of diameter 40 nm in a poly-methylmethacrylate ͑PMMA͒ layer of thickness 40 nm.…”

“…[3][4][5] The same cantilever can be used to detect the presence of a previously written data bit. 5 As the cantilever tip follows the contour of a data bit, the reduction in thermal impedance between the cantilever and the substrate causes a lower temperature rise in the heated cantilever, also shown in Fig. 1.…”

“…1 Several promising alternative data storage technologies that could surpass this limit involve the use of scanningprobe devices. 2 Thermomechanical data storage is one such technology, [3][4][5] demonstrating data density as high as 400 Gb/in 2 . 5 In thermomechanical data storage, a resistively heated atomic force microscope ͑AFM͒ cantilever writes a data bit by scanning over a polymer substrate.…”

“…2 Thermomechanical data storage is one such technology, [3][4][5] demonstrating data density as high as 400 Gb/in 2 . 5 In thermomechanical data storage, a resistively heated atomic force microscope ͑AFM͒ cantilever writes a data bit by scanning over a polymer substrate. Heat and force applied by the cantilever tip to the polymer cause it to soften and flow, writing a data bit, as shown in Fig.…”

Some insights into the structural relaxation of spin-cast, glassy polymer thin films

“…The widespread use of thin films in a range of applications and industries, from coatings, inks and lithography to nano-imprinting, optoelectronics, and memory devices 1 , has made the understanding of thin films, particularly the changes induced by structural relaxation and solvent evaporation, very important. There is a need to know if a film will change in dimensions after its deposition and how fast these changes will occur.…”