Hugo E. Rothuizen

Bio: Hugo E. Rothuizen is an academic researcher from IBM. The author has contributed to research in topics: Magnetic tape & Tape head. The author has an hindex of 35, co-authored 159 publications receiving 6606 citations. Previous affiliations of Hugo E. Rothuizen include École Polytechnique Fédérale de Lausanne.

The "millipede" - nanotechnology entering data storage

Abstract: 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/sup 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/spl times/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/sup 2/ have been achieved with the 32/spl times/32 array chip.

The Millipede: more than one thousand tips for future AFM data storage

Abstract: 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.

Printing meets lithography: soft approaches to high-resolution patterning

Abstract: We are developing a high-resolution printing technique based on transferring a pattern from an elastomeric stamp to a solid substrate by conformal contact. This is an attempt to enhance the accuracy of classical printing to a precision comparable with optical lithography, creating a low-cost, large-area, high-resolution patterning process. First, we introduce the components of this technique, called soft lithography, and review its evolution. Topics described in detail are the stamp material, stamp architecture, pattern design rules, and printing tools. The accuracy of the prints made by thin patterned elastomeric layers supported on a stiff and flexible backplane is then assessed, and defects are characterized using a new electrical metrology approach. This is followed by a discussion of various printing processes used in our laboratory: 1) thiol printing for high-resolution patterns of noble metals that may also be used as sacrificial masks; 2) confined contact processing with liquids in cavities or channels to chemically convert a substrate or deposit layers of materials or biomolecules; 3) printing of catalysts to mediate patterned deposition of metals; and 4) structured, light-guiding stamps for transferring high-resolution patterns into photoresists. Finally, we compare classical and high-resolution printing approaches, and describe their potential for emerging micro-and nano-scale patterning technologies.

"Millipede": a MEMS-based scanning-probe data-storage system

Abstract: Ultrahigh storage densities of up to 1 Tb/in./sup 2/ or more can be achieved by using local-probe techniques to write, read back, and erase data in very thin polymer films. The thermomechanical scanning-probe-based data-storage concept called Millipede combines ultrahigh density, small form factor, and high data rate. After illustrating the principles of operation of the Millipede, a channel model for the analysis of the readback process is introduced, and analytical results are compared with experimental data. Furthermore, the arrangement of data-storage fields as well as dedicated fields for servo and timing control is discussed, and system aspects related to the readback process, multiplexing, synchronization, and position-error-signal generation for tracking are introduced. Finally, the application of (d,k) modulation coding as a means to further increase areal density is presented, and the effect on the user data rates discussed.

Nanoscale thermal transport

Abstract: Rapid progress in the synthesis and processing of materials with structure on nanometer length scales has created a demand for greater scientific understanding of thermal transport in nanoscale devices, individual nanostructures, and nanostructured materials. This review emphasizes developments in experiment, theory, and computation that have occurred in the past ten years and summarizes the present status of the field. Interfaces between materials become increasingly important on small length scales. The thermal conductance of many solid–solid interfaces have been studied experimentally but the range of observed interface properties is much smaller than predicted by simple theory. Classical molecular dynamics simulations are emerging as a powerful tool for calculations of thermal conductance and phonon scattering, and may provide for a lively interplay of experiment and theory in the near term. Fundamental issues remain concerning the correct definitions of temperature in nonequilibrium nanoscale systems. Modern Si microelectronics are now firmly in the nanoscale regime—experiments have demonstrated that the close proximity of interfaces and the extremely small volume of heat dissipation strongly modifies thermal transport, thereby aggravating problems of thermal management. Microelectronic devices are too large to yield to atomic-level simulation in the foreseeable future and, therefore, calculations of thermal transport must rely on solutions of the Boltzmann transport equation; microscopic phonon scattering rates needed for predictive models are, even for Si, poorly known. Low-dimensional nanostructures, such as carbon nanotubes, are predicted to have novel transport properties; the first quantitative experiments of the thermal conductivity of nanotubes have recently been achieved using microfabricated measurement systems. Nanoscale porosity decreases the permittivity of amorphous dielectrics but porosity also strongly decreases the thermal conductivity. The promise of improved thermoelectric materials and problems of thermal management of optoelectronic devices have stimulated extensive studies of semiconductor superlattices; agreement between experiment and theory is generally poor. Advances in measurement methods, e.g., the 3ω method, time-domain thermoreflectance, sources of coherent phonons, microfabricated test structures, and the scanning thermal microscope, are enabling new capabilities for nanoscale thermal metrology.

Soft Lithography in Biology and Biochemistry

Abstract: ▪ Abstract Soft lithography, a set of techniques for microfabrication, is based on printing and molding using elastomeric stamps with the patterns of interest in bas-relief. As a technique for fabricating microstructures for biological applications, soft lithography overcomes many of the shortcomings of photolithography. In particular, soft lithography offers the ability to control the molecular structure of surfaces and to pattern the complex molecules relevant to biology, to fabricate channel structures appropriate for microfluidics, and to pattern and manipulate cells. For the relatively large feature sizes used in biology (≥50 μm), production of prototype patterns and structures is convenient, inexpensive, and rapid. Self-assembled monolayers of alkanethiolates on gold are particularly easy to pattern by soft lithography, and they provide exquisite control over surface biochemistry.