A noncontact atomic force microscope operated at low-temperature is used for vertical manipulation of selected single atoms from the Si(111)7×7 surface. The strong repulsive short-range chemical force interaction between the closest atoms of both tip apex and surface during a soft nanoindentation leads to the removal of a selected silicon atom from its equilibrium position at the surface without additional perturbation of the 7×7 unit cell. Deposition of single atom on a created vacancy at the surface is achieved. These manipulation processes are purely mechanical, since neither bias voltage nor voltage pulse is applied between probe and sample.

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A brief review of some applications of nanotechnology to information storage is given with the focus on self-assembled nanoporous alumina templates for patterned media. Ordered nanoporous alumina templates were fabricated by self-assembly technology. A two-step anodization process was also carried out to obtain templates with straight pores without removing the aluminum and barrier layer. Polycrystalline structure was observed with a grain size of about two micrometers in which the pores were almost perfect hexagonally ordered. The pore arrays exhibit different orientation along the boundaries of neighboring grains. Nanopatterning implemented by electron-beam lithography demonstrates a potential for writing concentric circular patterns with linewidths as small as 30nm.

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This paper presents bio-inspired nanoactuators and banched electrode nanodetectors for high-precision Micro Electro Mechanical System (MEMS) applications. Fabrication errors and electrical noise in MEMS cause the major difficulty to achieve high-precision actuation and detection capabilities. For the nano-precision actuation, we solve the fabrication instability and electrical noise problems using bio-inspired digital actuators with nonlinear mechanical modulators. For the high-precision capacitive detection, we present a branched finger electrodes using high-amplitude anti-phase sensing signals. We also demonstrate the potential applications of the nanoactuators and nanodetectors to high-precision positioning MEMS.

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Data-storage using near-field optical microscopy is a promising technology for the breakthrough of high-density optical disk memory since wavelength limit of conventional lens-optics is not applied. We have proposed a MEMS for the near-field optical data storage, which consists of integrated optical micro-probes and a micro media-translation-table. In the first part of the presentation, three-dimensional lithography based on the bulk micromachining using resist spray coater is described. Secondly, we describe the integration of waveguide, micro-pinhole tip, cantilever, and photodiode for a MEMS probe. The media-translation-table consisting of the inverted scratch drive actuators is also described.

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Hard disk drives have crosed the 90,000 tracks-per-inch mark in year 2002 without using the much desired dual-stage actuators. In this paper, we will discuss some possible problems facing the servo system design in servo track writer for achieving narrower than 5 micro-inch track width. Problems such as feedback information configuration, control system structure, servo problem formulation, and servo loop shaping, will be discussed.

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An improved design of piezoelectrically -driven suspension was developed to enhance magnification of stroke as well as to improve dynamic response. The design adopted flexural rotation together with rigid-body rotation to achieve stroke amplification, and its base was reinforced to increase the first tensional frequency that affects accurate HDD head positioning.

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In this paper, a new micro actuator is discussed to realize highly precise track following for a HGA (head gimbals assembly) of a spinstand system. The actuator is constructed with a piezoelectric element (PZT) and a stroke amplification mechanism, and is designed by using FEM (finite element method) analysis. The control system is designed to show high robustness against HGA variations of any kinds of HGA's.

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We have developed a novel piezoelectric microactuator for the head-slider drive dual-stage actuator systems in magnetic disk drives. This microactuator is based on a symmetrical structure and a symmetrical operation. The piezoelectric actuator devices used in the system are simple rectangular multilayered structure. A prototype model with pico-slider and the head suspension has been tested to demonstrate 0.8μm displacement at a dc applied voltage of 30V and fundamental resonant frequency over 20kHz.

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This paper presents a cost-effective micromachined electrostatic actuator for read/write (R/D) head tracking positioning in hard disk drives (HDDs). Key issues on processing are discussed in consideration of integration with the process of R/W head fabrication.

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Real random numbers produced by a physical process are important for many applications in cryptography. This report presents a mechanism for collecting random numbers based on physical noise sources in a standard hard disk drive. We apply and describe statistical tests to demonstrate that high quality random numbers can be produced at a speed of up to 835200 bits/sec. As this process can be implemented on any hard disk drive, no additional hardware is needed to obtain these numbers.

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Future Consumer Electronic (CE) applications will make widespread use of existing desktop Hard Disk Drive (HDD) technology for audiovisual (A/V) recording and playback purposes. In mobile applications storage drives may encounter more shock & vibrations compared to office or in home applications. Philips as a system integrator has applied a new tool to test the sensitivity of storage devices under such conditions. In this tool the Streaming Performance of the drive is monitored. It is concluded that some hard disk drives will have difficulties in meeting AV streaming criteria at vibration levels below those provided in the Shock & Vibration specifications. This tool is also useful to analyze specific frequencies for which the drive is particularly sensitive and for which special excitation prevention measures should be considered in the end product design.

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We have developed a dedicated erasing device for higher density Hard Disk Drive (HDD) which uses highly efficient permanent magnet matrix. This eraser magnet has achieved complete erasure of the servo pattern on the disk with no degradation of the spindle motor magnet. In this paper, we present the development method and experimental results of the disk eraser magnet matrix

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In this paper, we propose a new correction algorithm of servo track writing error based on iterative learning control technique. Our correction algorithm can learn iteratively the servo track writing error as accurately as is desired. Furthermore, our algorithm is robust to system model errors, is computationally simple, and has fast convergence rate. In order to demonstrate the practical use of our work, we present some simulation results for a commercially available disk drive.

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The notch filter is usually used to suppress mechanical resonance of an actuator. However, the resonance frequency can vary due to manufacturing tolerance and environmental factors like temperature. In this paper, we present an adaptive digital notch filter that identifies the resonance frequency of the actuator precisely and adjusts automatically its center frequency. For the identification of resonance frequency, we propose a new estimation filter and its tuning algorithm. In order to demonstrate the practical use of our work, we present some experimental results for a commercially available disk drive.

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This paper presents an active vibration rejection scheme using a compound actuator in hard disk drive. The PZT in the actuator is used as a sensor to measure vibration of the actuator. Application results demonstrate effectiveness of the proposed scheme.

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In HDD single stage servo system that uses Voice Coil Motor (VCM) as the only actuator, the sensitivity hump appears unavoidably due to the Bode's Integral Theorem (BIT), resulting in amplification of disturbances at high frequency band. This paper studies the sensitivity limitation in HDD dual-stage servo system. A low relative degree micro-actuator controller and the compensation method termed "Near-Perfect Modeling" (NPM) for both poles and zeros of the micro-actuator is used to suppress the sensitivity hump to as low as possible. Experimental results show that the sensitivity hump of the dual-stage servo loop can be reduced to very close to 0 dB. As such, high frequency disturbances would not be amplified by the servo loop and the Track Mis-Registration (TMR) would be reduced.

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In this paper, acceleration feedforward control based on adaptive identification for hard disk drives is proposed. To realize adaptive identification, external disturbance is estimated by Disturbance Observer and used for identification. By this means, the feedfoward controller can be relized without indirect calculation as conventional methods. Some experimental results where a disk drive is shaken are shown to verify the effectiveness of the proposed method.

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In this paper, a mesh-free numerical method (least square finite difference scheme) is presented to solve the slider air bearing problems of hard disk drives. For each specified attitude, the air bearing pressure is obtained by solving the generalized Reynolds equation using the mesh-free method. The method with second order accuracy directly approximates the derivatives in the differential equations. The discretized nonlinear systems of equations are solved by Successive Over-Relaxation (SOR) implementation. Finally, the steady-state flying attitude of a slider subject to pro-applied suspension force and torques is obtained by a Quasi-Newton iteration method.

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In order to examine molecular gas film lubrication (MGL)^[1] characteristics for spacings of several nanometers, the free mo lecular MGL equation, which involves the Poiseuille flow rate and the shear stress coefficient for the free molecular flow region and takes surface assommodation effects into account, is established, The usefulness of the free molecular MGL equation is shown by calculating the basic characteristics of flying head sliders using disk and slider assommodation coefficients, α_0 and α_1,as a parameter.

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The aubic interpolated propagation (CIP) method ^[1], which is an effective numerical scheme for differential equations that include advection and nonadvection terms, is employed for the dynamic analyses of ultra-thin gas film lubrication using the molecular gas-film lubrication (MGL) equation ^[2]. 2-DOF slider dynamics with the spacing of several tens of nanometers caused by a running wavy disk and projections are investigated herein.

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The response of a pad slider, comprising a leading pad and a trailing pad, due to disk waviness was analyzed by computer simulation. Because pads on the air-bearing surface of the slider are able to occur two pressure peaks that happen severally on the leading edge and trailing edge of the air-bearing surface enabling a pitching motion of the slider, the slider can follow the disk waviness with a wavelength shorter than the slider length. However, the slider cannot follow the disk waviness with a wavelength that is shorter than the length of the pad.

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This paper reports results of further study of the data writing induced nano-deformation of slider body and flying height change of the head-slider. The work reported focuses on computer modeling of the relationship between local protrusion and nano-deformation of slider body, caused by writing induced internal heating, and flying height change of the head-slider. Results on how to reduce the flying height fluctuation caused by such deformation will also be presented. Work also extends to the optimization of slider ABS design so as to achieve both low flying height and high flying stability.

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The generalized and approximated formula of the van der Waals pressure for a multilayered system was newly developed. The generalized formula does not require any corrections by the component materials. Applying the generalized formula to an inclined flying head slider, the dependences of the static load-carrying capacity and limit spacing of flying on the PEPE film thickness were clarified.

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The authors build upon a HDI model including intermolecular forces to parametrically study dynamic instability. The effects of the following parameters governing the HDI are addressed : (1) intermolecular force, (2) air bearing stiffness, (3) air bearing damping, and (4) disk topography. Based on these studies, air bearing and disk topography design guidelines are outlined to maximize HDI stability due to intermolecular forces.

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Recent trend of high recording density and consequently low magnetic spacing in HDD technology has necessitated strict control of the mechanical flying height (FH) of the sliders above magnetic disk. The FH is typically measured on the glass disk with interferometric methods to determine the FH from interference light intensity. The intensity is often affected by the variation of the refractive index (n, k) of the air bearing surface (ABS). This paper describes efforts to (A) predict FH variation due to n, k variation from the principle of the FH testers commercially available, (B) Verify the relation of the FH-n, k relation from (A) by affecting the n, k value set-up on the FH testers and measuring the FH, and lastly, (C) apply the relation to correct FH values and demonstrate corrected value show better FH variation.

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Optical interferometry, amongst other techniques such as capacitive and the read back signal method, is a well established technique for the measurement of small displacements [1]. Previously, heterodyne interferometry [2] and phase-shifting interferometry [3] have been used to make high resolution measurement of such small displacements. However, these existing methods are generally only feasible for low speed measurement applications. A polarisation interferometer has been designed and built to measure dynamically the flying height down to near-contact.

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The disk take-off height (or glide avalanche) is a commonly used property of the disk in disk drives. Typically, the take-off height is defined as a pure disk property, influenced by the disk surface morphology and topography. However, at increasingly low slider flying heights, the take-off height also is strongly coupled with the slider air-bearing design. The flying height at which the interference exceeds a certain threshold is called the effective take-off height of the head-disk interface. We have determined that, the width of the slider trailing edge and slider dynamic pitch have a strong influence on the effective take-off height. We show that the head-disk durability is directly proportional to the effective take-off height. Therefore, the effective take-off height must be considered as one of the critical parameters in designing reliable disk drives.

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To reduce the risk of a head crash by reducing stiction/friction at head disk interface, friction reduction by micro-vibration was proposed and investigated for application in hard disk drive. A model head for investigating the friction control between a head and a disk was introduced. Both the effect of micro-vibration on friction and the influence of surface roughness on friction reduction by micro-vibration under micro-load conditions were discussed. It was found that micro-vibration of the model head is effective to reduce friction when a slider contacts a smooth disk.

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A micro-contact model for chemical-mechanical polishing (CMP) of Silicon wafer is presented. The model is developed on the basis of the Greenwood-Williamson elastic micro-contact mechanics. The atomic force microscope (AFM) is used as a polishing test apparatus to evaluate the removal rate by a single particle in a CMP slurry. Using this model and AFM, the simulation on polishing of SiO2 is performed. The model is evaluated by comparing the simulated polishing rate and that experimentally determined by real CMP processes. As a result, the simulation result and experiment result are in good agreement. It suggests that the combination of the model and AFM polishing test can be used to estimate the removal rate of SiO2 CMP and may be used to study the effects of different materials, slurry and operating condition on CMP process.

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Flow resistance of a water droplet confined between two hydrophobic surfaces has been investigated experimentally and factors contributing to the flow resistance have been studied. It was found that the flow resistance at low speeds is mainly caused by asymmetrical surface tension due to the contact angle hysteresis. On a rough hydrophobic surface a droplet remains almost symmetrical and exhibits extremely low friction. The flow resistance at high speeds is influenced by viscous force.

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This paper deals with the modeling of stress singularity at the interface edge between piezoelectric thin films and an elastic substrate. The electro-elastic problem of a transversely isotropic piezoelectric thin film attached on an elastic substrate is treated theoretically. Emphasis is placed on the investigation of the singularity in the stress field at the free edge of interface. The eigen-equation determining the order of the singularity is derived. Numerical results for two edge geometries are presented for PZT film/silicon substrate combinations.

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In order to solve the over etching problem which leads to low production yield in the microcantilever process, a new fabrication process by using DRIE etching of silicon from the front side of the silicon wafer has been developed. Silicon free membrane microcantilever with Lead Zirconate Titanate (PZT) thin films 1 to 2 μm in thickness have been successfully fabricated with 100% yield by this new process. Annealing temperature is critical to the property of the PZT film prepared by sol-gel method.

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High-bandwidth and high-accuracy servo actuation of the recording head is necessary for the future high areal density of hard disk drives (HDD). A 3-D electrostatic microactuator for dual-stage servo system of HDD has been developed in this paper. Parallel-upstanding comb drives are utilized, and interlapped-L flexures are introduced for the microactuator, which make the actuator a thick 3-D structure with a high aspect ratio. The 3-D microactuator is fabricated in a bulk silicon wafer bonded to a Pyrex glass substrate by using MEMS technologies, and it is assembled between the slider and suspension's gimbal. Simulated model has predicted the 0.58-μm displacement and 2.1-kHz resonant frequency of the microactuator with a low driving voltage of 30V.

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Present study reports micro-rheometry of pressurized lubricant oils such as the measurement of density and viscosity employing a diamond-anvil pressure cell (DAC). High pressure viscosity and volume change were shown up to 2 GPa and 6 GPa, respectively. And some considerations for lubricant's micro-nanorheology was also mentioned.

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In this article, to realize super-high storage density and high precision memory using polycarbonate and polyolefin as a media, nanometer-scale processing properties of polycarbonate (PC), polyolefin (PO), fluorocarbon plasma-treated and DLC films coated polycarbonate and polyolefin were investigated with the tip sliding of atomic force microscope (AFM). The mechanical and viscoelastic properties of modified PC and PO are improved obviously comparing with those of untreated PC and PO. Microwear depths of 3 nm DLC PC and were decreased from 24.1 nm to 0.48 and that of 3 nm DLC PO was decreased from 29.6 nm to 1.07nm. Stiffness of modified PC and PO show a tendency toward low. It is considered that molecular interaction between a tip and processed surface became weak due to C-F bonding and DLC structure.

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