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Cantilever arrays are employed to increase the throughput of imaging and manipulation at the nanoscale. We present a fabrication process to construct cantilever arrays with nanotips that show a uniform tip-sample distance. Such uniformity is crucial, because in many applications the cantilevers do not feature individual tip-sample spacing control. Uniform cantilever arrays lead to very similar tip-sample interaction within an array, enable non-contact modes for arrays and give better control over the load force in contact modes. The developed process flow uses a single mask to define both tips and cantilevers. An additional mask is required for the back side etch. The tips are self-aligned in the convex corner at the free end of each cantilever. Although we use standard optical contact lithography, we show that the convex corner can be sharpened to a nanometre scale radius by an isotropic underetch step. The process is robust and wafer-scale. The resonance frequencies of the cantilevers within an array are shown to be highly uniform with a relative standard error of 0.26% or lower. The tip-sample distance within an array of up to ten cantilevers is measured to have a standard error around 10 nm. An imaging demonstration using the AFM shows that all cantilevers in the array have a sharp tip with a radius below 10 nm. The process flow for the cantilever arrays finds application in probe-based nanolithography, probe-based data storage, nanomanufacturing and parallel scanning probe microscopy.

The Micronium is a musical instrument fabricated from silicon using microelectromechanical system (MEMS) technology. It is—to the best of our knowledge—the first musical micro-instrument fabricated using MEMS technology, where the actual sound is generated by mechanical microstructures. The Micronium consists of mass-spring systems that are designed to resonate at audible frequencies. Their displacement is measured by comb drives and is used as the audio signal to drive a loudspeaker. The instrument's sounds are pure sine waves. An extensive set of measurements of individual resonators is presented and discussed. Quality factor measurements at various ambient pressures show that an ambient pressure of 1 mbar results in a note duration of 1 s. The realized frequency deviates considerably from the designed resonator frequency. Measurement results of many resonators are shown to obtain understanding of this deviation. Initial experiments with electrostatic tuning using variable-gap comb drives show a tuning ratio of 5% maximum, depending on the resonator frequency. An audio recording of the instrument is included as a supplementary MP3 file.

Co/Pt multilayer dots with perpendicular anisotropy and with diameters of 250 and 350 nm were fabricated on top of a Hall cross configuration. The angular dependence of the magnetic reversal of the individual dot was investigated by Anomalous Hall effect measurements. At near in-plane angles (85° with the magnetic easy axis) the dot switches partially into a stable two-domain state. This allows for separate analysis of the angular dependence of both the field required for nucleation of a reversed domain, and the field required for depinning of the domain wall. The angular dependence of the depinning field fits accurately to a 1/cos(θ) behavior, whereas the angular dependence of the nucleation field shows a minimum close to 45°. The latter dependency can be accurately fitted to the modified Kondorsky model proposed by Schumacher [1] F. Schumacher. Journal of Applied Physics, 70 (1991), p. 3184. | View Record in Scopus | | Full Text via CrossRef | Cited By in Scopus (5)[1].

Accurate manipulation of small objects is becoming more and more important. Besides accurate manipulation, the demand for small manipulators is also increasing. Some examples are high-density data storage, (digital) light processing, accelerometers, rate sensors, and the use of cantilevers in atomic force microscopy. Another example where small and accurate manipulators are beneficial is inside an electron microscope, for sample as well as beam manipulation. This work presents the design, fabrication and experimental validation of a thermal displacement sensor for accurate measurement of the position of a MEMS stage. The sensor was integrated with the manipulation stage in a singlemask production process.

This work presents a MEMS displacement sensor based on the conductive heat transfer of a resistively heated silicon structure towards an actuated stage parallel to the structure. This differential sensor can be easily incorporated into a silicon-on-insulator-based process, and fabricated within the same mask as electrostatic actuators and flexure-based stages. We discuss a lumped capacitance model to optimize the sensor sensitivity as a function of the doping concentration, the operating temperature, the heater length and width. We demonstrate various sensor designs. The typical sensor resolution is 2 nm within a bandwidth of 25 Hz at a full scale range of 110 µm.

This paper reports on the piezoelectric-microelectromechanical system micro-fabrication process and the behavior of piezoelectric stacks actuated silicon cantilevers. All oxide layers in the piezoelectric stacks, such as buffer-layer/bottom-electrode/film/top-electrode: YSZ/SrRuO3/Pb(Zr,Ti)3/SrRuO3, were grown epitaxially on the Si template of silicon-on-insulator substrates by pulsed laser deposition. By using an analytical model and finite element simulation, the initial bending of the cantilevers was calculated. These theoretical analyses are in good agreement with the experimental results which were determined using a white light interferometer. The dependences of the cantilever displacement, resonance frequency and quality factor on the cantilever geometry have been investigated using a laser-Doppler vibrometer. The tip displacement ranged from 0.03 to 0.42 µm V−1, whereas the resonance frequency and quality factor values changed from 1010 to 18.6 kHz and 614 to 174, respectively, for the cantilevers with lengths in the range of 100–800 µm. Furthermore, the effect of the conductive oxide electrodes on the stability of the piezoelectric displacement of the cantilevers has been studied.

In this work we describe the design, fabrication, and testing of a mass-balanced planar x/y-scanner designed for parallel-probe data storage applications. The scanner is actuated by comb drives, whose finger shape is improved using finite-element analysis to increase the force output. A mass-balancing concept is used for in-plane shock resistance; in the out-of-plane direction passive shock resistance is achieved using 1:40 aspect-ratio springs that are fabricated by deep reactive ion etching through the full thickness of a [email protected] wafer. A prototype device is presented and its performance is reported.

A method of heat-assisted magnetic recording (HAMR) potentially suitable for probe-based storage systems is characterized. In this work, field emission current from a scanning tunneling microscope (STM) tip is used as the heating source. Pulse voltages of 2-7 V were applied to a CoNi/Pt multilayered film fabricated on either bare silicon or oxidized silicon substrates. Different types of Ir/Pt and W STM tips were used in the experiment. The results show that thermally recorded magnetic marks are formed with a nearly uniform mark size of 170 nm on the film fabricated on bare silicon substrate when the pulse voltage is above a threshold voltage. The mark size becomes 260 nm when they are written on the identical film fabricated on an oxidized silicon substrate. The threshold voltage depends on the material work function of the tip, with W having a threshold voltage about 1 V lower than Pt. A synthesized model, which contains the calculation of the emission current, the simulation of heat transfer during heating, and the study of magnetic domain formation, was introduced to explain experimental results. The simulation agrees well with the experiments. © 2005 Elsevier B.V. All rights reserved.

A method of heat-assisted magnetic recording (HAMR) potentially suitable for probe-based storage systems is characterized. In this work, field emission current from a scanning tunneling microscope (STM) tip is used as the heating source. Pulse voltages of 3-7 V with a duration of 500 ns were applied to a CoNi/Pt multilayered film which is fabricated on a bare silicon and oxidized silicon, respectively. For both substrates, write threshold voltage of 4 V was observed. Above threshold, mark size was 170 and 260 nm for the films on bare silicon and oxidized silicon, respectively. A model of 2-D heat transfer in a multilayered film structure was applied and the mark size difference was explained by the thermal conductivity of the substrate. © 2006 Elsevier B.V. All rights reserved.

The thermal dependence and distribution of the switching fields of arrays of magnetic Co50Ni50/Pt nanodots has been studied. These dots, with a diameter of 90 nm, are arranged in a hexagonal pattern with a periodicity of 300 nm. Field-dependent magnetic force microscopy was used to measure the switching field distribution of the array, which was found to range from 80 to 192 kA/m, a value which is confirmed by vibrating sample magnetometer measurements. Additionally, the temperature dependence on the collective behaviour of the switching fields of the array has been investigated. The energy barrier at zero field was estimated to have a value in between 1.8×10−19 and 2.1×10−19 J. Combining this value with the effective anisotropy determined by torque measurements, the switching volume can be estimated to lie in between 1.2×103 and 1.4×103 nm3.

A method of fabrication of patterned magnetic nanodots by means of laser interference lithography is presented. This method includes the use of a diluted positive photoresist, and modifcations in the etching angle and acceleration voltage of the ion beam etching process. Vertical standing waves were suppressed by using a high exposure dose (supra-exposure) instead of an antireflective coating. Field dependent magnetic force microscopy was used to measure the switching field distribution, which was found to range from 80 to 192 kA/m.

In this chapter Magnetic Force Microscopy is treated in detail. The emphasis is on high resolution and the design and realisation of MFM tips.

Heat-assisted magnetic probe recording on a CoNi/Pt multilayered film is demonstrated by delivering a current through a magnetic force microscopy tip into the recording medium, in combination with an external magnetic field. Without local heating by the probe, no bits could be written because the external field exceeds a level that demagnetizes the medium in its entirety due to local variations in the coercivity of the medium. In contrast, magnetic bits were successfully written by the heat-assisted magnetic probe recording into a saturated medium even if there was no external field, because of the demagnetization field from the surrounding of the heated area. A magnetic bit as small as 80nm in diameter was obtained by this method.

The areal bit density of magnetic disk recording has made a colossal increase over the last decades. Extrapolation leads to recording parameters not likely to be achieved without changes in the present way of storing magnetic data. One of the potential solutions is the use of patterned media, which should consist of a regular two-dimensional array of single domain dots with large uniaxial magnetic anisotropy. Such media will shift the super paramagnetic limit positively in comparison with the present thin film media.Theoretically, a bit density in the order of Tbpsi is possible. This paper will discuss the most valuable methods for preparing patterned media.

Enkele jaren geleden begon het allemaal, de fundamentele grenzen van de harde schijf kwamen in zicht. Het grootste probleem van de harde schijf de is de één kop per kant strategie. Deze strategie schaalt slecht: de hoeveelheid data die kan worden opgeslagen wordt snel groter, maar de accesstijd en datarate blijven sterk achter[1]. De oplossing: probe recording. In dit soort data opslagsystemen werken grote aantallen lees-schrijfkoppen samen om een hoge datarate te verkrijgen. Bovendien schaalt het aantal kopjes lineair met de capaciteit van het systeem[2] [3]. De ontwikkeling is in volle gang, maar wat kunnen we op dit gebied verder nog verwachten voor de toekomst?

Thin-film yoke-type magnetoresistive (MR) tape heads with eight channels have been used for scanning magnetoresistance microscopy. The NiFe read flux guides of the channels have been trimmed down from 12 /spl mu/m to widths varying between 5 /spl mu/m and 100 nm by focused ion-beam milling with Ga/sup +/ ions. The tape-bearing surface of the milled regions has been reconstructed in situ by the local deposition of Pt. Tracks with a minimum bit length of 1 /spl mu/m have been written on Co-Ni-O metal evaporated tape and Co-/spl gamma/-Fe/sub 2/O/sub 3/ particulate tape with trimmed and untrimmed write channels and have been successfully imaged with all the trimmed read channels. A linear decrease in readback voltage across the MR sensor is observed for channels possessing flux guides trimmed down to 2 /spl mu/m, in agreement with finite-element modeling of the trimmed heads. The severe attenuation in readback voltage observed for flux guides trimmed below 2 /spl mu/m is attributed to a combination of micromagnetic effects. Additionally, damage to the NiFe from Ga/sup +/ ion implantation may make a minor contribution to the loss in sensor performance. A 65% drop in readback voltage is observed for a channel possessing a flux guide that was trimmed by 98.3% to 200 nm.

The domain structure and the switching field of Co50 Ni50 /Pt multilayer dots, prepared by laser interference lithography,were micromagnetically simulated. The simulations were carried out with a three-dimensional simulation package, optimized for large-scale problems. The single-domain state is the lowest energy state for dots with a diameter below 75 nm. The switching field was computed by using suitable minimization techniques, and was used to analyze the effect of size, dot shape and edge defects.

De harde schijf gaat langzaam ten onder aan zijn eigen succes, zo beschreven we in het meinummer van Natuur & Techniek wetenschapsmagazine. De snelle capaciteitsverhoging gaat niet gepaard met een gelijke verbetering van de de leessnelheid en de toegangstijd. Twente loopt voorop in de zoektocht naar een geschikte opvolger.

Scanning magneto-resistance microscopy has been performed with thin film yoke-type magneto-resistive tape heads possessing eight channels. The read flux guides of these channels have been trimmed down from 24 μm to widths varying between 5.5 μm and 148 nm by focused ion beam milling with Ga+ ions. Tracks written on ME tape with an untrimmed write channel have been successfully imaged with all the trimmed channels. A significant attenuation (>5%) of read-back voltage across the MR sensor is only observed for channels possessing flux guides trimmed by 77% to 5.5 μm. A 52% (6 dB) drop in read-back voltage is observed for a channel possessing a flux guide trimmed by 99.4% to 148 nm.

The effect of intertrack intersymbol interference in a magnetic patterned medium is studied. A two-dimensional (2-D) channel code is proposed, dedicated to perpendicularly magnetized media without soft underlayer, which exhibit read pulses showing overshoot. Read pulse shapes were investigated using a magnetic-force microscope tip scanning the patterned medium row-by-row. To test different codes, a bit-detection simulation program was developed to generate large amounts of data on which bit error rates can be measured. Application of the 2-D channel code, which implies recording of particular dot positions with fixed bits ("ones", "zeros"), resulted in the elimination of 2-D worst-case bit patterns and a subsequent reduction of detected-bit errors. The accompanying redundancy of 22% is inevitable for this type of 2-D code.

A method of heat-assisted magnetic recording potentially suitable for probe-based storage systems is characterized. Field emission current from a scanning tunnelling microscope tip is used as the heating source. Pulse voltages of 5 V were applied to a granular CoNi/Pt multilayered film. Experimental results show that an average mark size of 90–120 nm was achieved with the minimum of 70 nm. A model of dynamic domain formation is built to quantitatively explain the experimental results. It agrees with experiments. Based on this model, we will be able to figure out the proposals to achieve small marks for ultra-high recording density.

We investigate the energy consumption and seek-time performance of different actuator types for nanopositioners, with emphasis on their use in a parallel-probe-based data-storage system. Analytical models are derived to calculate the energy consumption and performance of electrodynamic (coil and permanent magnet) and comb-drive actuators. The equations are used to simulate the operation of probe-storage devices with these actuator types under a realistic file system load. The electrostatic comb-drive actuators are more energy efficient than the electrodynamic actuators, by an order of magnitude for slow movements and a factor of 2.5 for high-acceleration movements. Overall in a probe-storage device, comb-drive actuation is a factor of 3.3 more energy efficient than electrodynamic actuation, at the same level of performance. The analytical model presented in this work can be used to direct the optimization of nanopositioners and their use, for example, in terms of the data layout on the medium and the ‘shutdown’ policy of probe-storage devices.

A method of heat-assisted magnetic recording (HAMR) potentially suitable for probe-based storage systems is characterized. In this work, field emission current from a scanning tunneling microscope (STM) tip is used as the heating source. Pulse voltages of 2-7 V with a duration of 500 ns were applied to a CoNi/Pt multilayered film. Different types of Ir/Pt and W STM tips were used in the experiment. The results show that thermally recorded magnetic marks are formed with a nearly uniform mark size of 170 nm when the pulse voltage is above a threshold voltage. The threshold voltage depends on the material work function of the tip, with W having a threshold voltage about 1 V lower than Pt. The emission area of our tip-sample system derived from an analytic expression for field emission current is approximately equal to the mark size, and is largely independent of pulse voltage. This emission area is large compared to lateral heat diffusion in the film. Thus higher applied voltages lead to higher peak temperatures in the model of the write process, but the mark diameter remains relatively unchanged.

The transfer functions of tips with various sharpened tip ends were calculated and the resolution of these tips was estimated by considering the resolution limit due to thermal noise at room temperature. The tip having an ellipsoidal tip end (ellipsoidal tip) is found to be a suitable candidate for high-resolution magnetic force microscopy. Sharpening of the flat tip end makes zero signal frequencies disappear for tips with ellipticities larger than tan45/spl deg/. The sensitivity shows a maximum around an ellipticity of tan80/spl deg/. The ellipsoidal tip shows a much smaller tip thickness dependence compared to the tip having a flat tip end because only the tip end mainly contributes to signals in case of the ellipsoidal tip.

Throughout the ages humanity has stored data in order to preserve important information for generations to come. As the years have progressed the amount of data that can be stored efficiently has increased tremendously, the lifespan of this type of data storage however is severely limited. Within this paper we investigate the possibility to store data by encapsulating W in a SiN matrix.We show that using accelerated thermal aging the possible lifespan of this medium can be investigated and expected to reach well into the millions of years, preserving data for thousands of future generations. The first steps into fabrication of such a medium are discussed.

This paper presents a simple code to combat the 2-Dimensional Inter-Symbol Interference (2D-ISI) effect that is present in data storage on magnetic bit patterned media. Whether the ISI effect is constructive or destructive depends on the surrounding bits. Therefore, we propose a simple 2D coding scheme to mitigate the ISI effect. With this 2D coding scheme in square patterned media, every 2-by-3 array has one redundant bit which has the opposite or same value of one of its adjacent bits. Compared to the 2D coding scheme in \cite{Groenland2007} under the condition of the same areal density, the proposed 2D coding scheme increases the allowable bit-position jitter in square patterned media by 1\% at a BER of $10^{-4}$; while it allows the effective storage capacity to be increased by around 5.5\%.

This paper describes the design of a system for controlling the position of spherical paramagnetic microparticles that have an average diameter of 100 µm. The focus of this study lies in designing and implementing a system that uses microscopic images and electromagnets. Preliminary experiments have been done to verify the feasibility of the system to track and control the position of these particles. A vibrating sample magnetometer was used to determine the magnetic moment of the particles. Finite element method simulations were used to verify the magnetic behavior of the designed setup. The system was used to position the particles within 8.4µm of a setpoint, achieving speeds of up to 235µm s−1. We also demonstrated that the particle could follow a circular and a figure-eight path.

Scanning probe microscopy employing conductive probes is a powerful tool for the investigation and modification of electrical properties at the nanoscale. Application areas include semiconductor metrology, probe-based data storage and materials research. Conductive probes can also be used to emulate nanoscale electrical contacts. However, unreliable electrical contact and tip wear have severely hampered the widespread usage of conductive probes for these applications. In this paper we introduce a force modulation technique for enhanced nanoscale electrical sensing using conductive probes. This technique results in lower friction, reduced tip wear and enhanced electrical contact quality. Experimental results using phase-change material stacks and platinum silicide conductive probes clearly demonstrate the efficacy of the proposed technique. Furthermore, conductive-mode imaging experiments on specially prepared platinum/carbon samples are presented to demonstrate the widespread applicability of this technique.

The Young’s modulus of thin films can be determined by deposition on a micronsized Si cantilever and measuring the resonance frequency before and after deposition. The accuracy of the method depends strongly on the initial determination of the mechanical properties and dimensions of the cantilever. We discuss the orientation of the cantilever with respect to the Si crystal, and the inevitable undercut of the cantilever caused by process inaccuracies. By finite element modelling we show that the Young’s modulus should be used instead of the analytical plate modulus approximation for the effective Young’s modulus of Si cantilevers used in this work for both the 1 0 0 and 1 1 0 crystal orientation. Cantilever undercut can be corrected by variation of the cantilever length. As an example, the Young’s modulus of PbZr0.52Ti0.48O3 (PZT) thin films deposited by pulsed laser deposition (PLD) was determined to be 99 GPa, with 1.4 GPa standard error.

We present for the first time the combined measured piezoelectric and mechanical properties of epitaxial, (110) oriented Pb(ZrxTi1-x) (PZT) thin films grown on microfabricated silicon cantilevers using pulsed laser deposition (PLD, x=0.4, 0.52, 0.6 and 0.8). The grown PZT thin films develop a strong (110) preferred orientation, which results in an effective piezoelectric coefficient (d33,f) of 123 pm/V at the morphotropic phase boundary (Zr/Ti = 52/48). This value is 70% higher compared to sol-gel deposited films with an equal Young’s modulus [1]. The Young’s modulus of the PZT thin films was determined by measuring the shift in resonancefrequency of microfabricated cantilevers (shown in Fig. 1) both before and after deposition of the films by means of a scanning laser-Doppler vibrometer. To this end, we developed a model to calculate the Young’s modulus from the resonance frequency shift which includes an essential correction for the undesired undercut that is unavoidably introduced during the release of cantilevers [2]. The obtained Young’s modulus is independent on cantilever length, as expected. For a 100 nm thick PZT film with a Zr/Ti ratio of 60/40, the mean value of the measured Young’s modulus was found to be 122 GPa with a standard error of ± 1.3 GPa. Fig.2 shows an increase of the Young’s modulus of the PZT thin films with increasing Zr/(Zr+Ti) ratio. The PLD-PZT thin film presented in this work combines excellent piezoelectric properties with a high Young’s modulus, and is therefore a promising and exciting candidate for the active device layer in actuators and highly sensitive MEMS sensors.

We present for the first time the combined measured piezoelectric and mechanical properties of epitaxial, (110) oriented Pb(ZrxTi1-x) (PZT) thin films grown on microfabricated silicon cantilevers using pulsed laser deposition (PLD, x=0.4, 0.52, 0.6 and 0.8). The grown PZT thin films develop a strong (110) preferred orientation, which results in an effective piezoelectric coefficient (d33,f) of 123 pm/V at the morphotropic phase boundary (Zr/Ti = 52/48). This value is 70% higher compared to sol-gel deposited films with an equal Young’s modulus [1]. The Young’s modulus of the PZT thin films was determined by measuring the shift in resonancefrequency of microfabricated cantilevers (shown in Fig. 1) both before and after deposition of the films by means of a scanning laser-Doppler vibrometer. To this end, we developed a model to calculate the Young’s modulus from the resonance frequency shift which includes an essential correction for the undesired undercut that is unavoidably introduced during the release of cantilevers [2]. The obtained Young’s modulus is independent on cantilever length, as expected. For a 100 nm thick PZT film with a Zr/Ti ratio of 60/40, the mean value of the measured Young’s modulus was found to be 122 GPa with a standard error of ± 1.3 GPa. Fig.2 shows an increase of the Young’s modulus of the PZT thin films with increasing Zr/(Zr+Ti) ratio. The PLD-PZT thin film presented in this work combines excellent piezoelectric properties with a high Young’s modulus, and is therefore a promising and exciting candidate for the active device layer in actuators and highly sensitive MEMS sensors.

This research presents the fabrication of all-oxide LaNiO3/Pb(Zr,Ti)O3/LaNiO3 thin films for applications in piezoelectric microelectromechanical systems (piezoMEMS). All oxide layers are fabricated on 4-inch silicon-on-insulator (SOI) wafer using large-area pulsed laser deposition (PLD) by SolMateS B.V. The determined film-thickness variation is less than 5% over the total wafer area. PZT thin-film of 1-μm-thick exhibits (100) texture orientation. The optimization of the electromechanical responses for piezoelectric membranes is investigated experimentally. In the optimization of membrane- and electrode-geometries, Pb(Zr,Ti)O3 (PZT) actuators consisting of a variety of membrane type, membrane diameter and electrode coverage are fabricated using microfabrication processes and characterized by laser Doppler interferometer for piezoelectric responses, like displacement and resonance frequency. The fabricated 500-μm-diameter PZT membrane provides high central displacement of 26 nm/V at a constant frequency well below its first resonance frequency (fr = 330 kHz). The results also indicated that the membrane diameter has a dominant effect on the magnitude of the out-of-plane displacement and the resonance frequency. The electrode-size to membrane-diameter ratio or electrode coverage is important and may be tailored to optimize the displacement. Electrode coverage of 36% produces the optimum displacement. Moreover, it shows an excellent long-term stability of membrane actuators with a displacement remains of about 95% after 10 billion actuations, by using the conductive-oxide LaNiO3 (LNO) layers as the electrodes.

Accurate manipulation of small objects is becoming more and more important. Besides accurate manipulation, the demand for small manipulators is also increasing. Some examples are high-density data storage, (digital) light processing, accelerometers, rate sensors, and the use of cantilevers in atomic force microscopy. Another example where small and accurate manipulators are beneficial is inside an electron microscope, for sample as well as beam manipulation. This work presents the design, fabrication and experimental validation of a thermal displacement sensor for accurate measurement of the position of a MEMS stage. The sensor was integrated with the manipulation stage in a singlemask production process.

This research presents the fabrication of all-oxide LaNiO3/Pb(Zr,Ti)O3/LaNiO3 thin films for applications in piezoelectric microelectromechanical systems (piezoMEMS). All oxide layers are fabricated on 4-inch silicon-on-insulator (SOI) wafer using large-area pulsed laser deposition (PLD) by SolMateS B.V. The determined film-thickness variation is less than 5% over the total wafer area. PZT thin-film of 1-μm-thick exhibits (100) texture orientation. The optimization of the electromechanical responses for piezoelectric membranes is investigated experimentally. In the optimization of membrane- and electrode-geometries, Pb(Zr,Ti)O3 (PZT) actuators consisting of a variety of membrane type, membrane diameter and electrode coverage are fabricated using microfabrication processes and characterized by laser Doppler interferometer for piezoelectric responses, like displacement and resonance frequency. The fabricated 500-μm-diameter PZT membrane provides high central displacement of 26 nm/V at a constant frequency well below its first resonance frequency (fr = 330 kHz). The results also indicated that the membrane diameter has a dominant effect on the magnitude of the out-of-plane displacement and the resonance frequency. The electrode-size to membrane-diameter ratio or electrode coverage is important and may be tailored to optimize the displacement. Electrode coverage of 36% produces the optimum displacement. Moreover, it shows an excellent long-term stability of membrane actuators with a displacement remains of about 95% after 10 billion actuations, by using the conductive-oxide LaNiO3 (LNO) layers as the electrodes.

We determined the Young’s modulus of pulsed laser deposited epitaxially grown PbZr0.52Ti0.48O3 (PZT) thin films on microcantilevers by measuring the difference in cantilever resonance frequency before and after deposition. By carefully optimizing the accuracy of this technique, we were able to show that the Young’s modulus of PZT thin films deposited on silicon is dependent on the in-plane orientation, by using cantilevers oriented along the 1 1 0 and 1 0 0 silicon directions. Deposition of thin films on cantilevers affects their flexural rigidity and increases their mass, which results in a change in the resonance frequency. An analytical relation was developed to determine the effective Young’s modulus of the PZT thin films from the shift in the resonance frequency of the cantilevers, measured both before and after the deposition. In addition, the appropriate effective Young’s modulus valid for our cantilevers’ dimensions was used in the calculations that were determined by a combined analytical and finite-element (FE) simulations approach. We took extra care to eliminate the errors in the determination of the effective Young’s modulus of the PZT thin film, by accurately determining the dimensions of the cantilevers and by measuring many cantilevers of different lengths. Over-etching during the release of cantilevers from the handle wafer caused an undercut. Since this undercut cannot be avoided, the effective length was determined and used in the calculations. The Young’s modulus of PZT, deposited by pulsed laser deposition, was determined to be 103.0 GPa with a standard error of ± 1.4 GPa for the 1 1 0 crystal direction of silicon. For the 1 0 0 silicon direction, we measured 95.2 GPa with a standard error of ± 2.0 GPa.

In this thesis techniques are developed to read out nanoscale probes and arrays of probes.The main targeted application area is probe-based data storage.The work also contributes to other areas, such as metrology, biological sensing, materials research and nano-electro-mechanical switches. First, an exhaustive literature review of the accomplishments within probe storage is presented. It is found that optical readout techniques are used extensively in applications using probes; however, the very demanding application probe storage is not amongst them. Optical readout of probes offers reliability, high-speed, low noise and low complexity. It has to be extended to operation on arrays of probes for successful implementation in probe storage. The first technique that is developed in this work is parallel....

In this thesis techniques are developed to read out nanoscale probes and arrays of probes.The main targeted application area is probe-based data storage.The work also contributes to other areas, such as metrology, biological sensing, materials research and nano-electro-mechanical switches. First, an exhaustive literature review of the accomplishments within probe storage is presented. It is found that optical readout techniques are used extensively in applications using probes; however, the very demanding application probe storage is not amongst them. Optical readout of probes offers reliability, high-speed, low noise and low complexity. It has to be extended to operation on arrays of probes for successful implementation in probe storage. The first technique that is developed in this work is parallel....

The era of infinite storage seems near. To reach it, data storage capabilities need to grow, and new storage technologies must be developed.This thesis studies one aspect of one of the emergent storage technologies: optimizing electrostatic combdrive actuation for a parallel probe-based data storage system. It is no longer possible to store all created information. New storage technologies must be developed as current commercial technologies reach their fundamental limits. One promising technology is parallel probe-based data storage, using a nanometre-scale probe to write data on a moving platform. The working principle is very similar to that of a record player applied in parallel on the nano scale. In order to access all bits on the storage medium, a nano-positioner, or scanner, is used to move the storage medium relative to the read-out probes. Several nano-positioner designs for probe data storage are found in the literature. It is not clear which actuator type (electromagnetic, electrostatic, or piezoelectric) is most suited for probe data storage. We replaced the electrodynamic actuators by comb-drives in the scanner prototype by IBM, to enable a direct comparison. e comb-drive’s areal efficiency is low, due to a relatively low electrostatic force. e comb-drive finger profile is optimized for probe data storage, for an increased shock resistance. e suitability of electromagnetic and electrostatic actuation is, among others, determined by their energy consumption.Three (partly) hypothetical scanner designs using electrodynamic, electromagnetic and electrostatic comb-drive actuators are described. Their performance is approximately equal, however electrostatic comb-drive actuation requires an order of magnitude less energy. Equations are presented for further investigations into the performance and energy consumption of the different actuation types for different file-system use cases. We succeeded in making music with MEMS structures, and named our microinstrument ‘the micronium’. Due to fabrication inaccuracies, the instrument is outof- tune and requires tuning. Besides teaching students about MEMS technology in a fun way, the micronium succeeded in presenting MEMS technology to a broad audience.

The era of infinite storage seems near. To reach it, data storage capabilities need to grow, and new storage technologies must be developed.This thesis studies one aspect of one of the emergent storage technologies: optimizing electrostatic combdrive actuation for a parallel probe-based data storage system. It is no longer possible to store all created information. New storage technologies must be developed as current commercial technologies reach their fundamental limits. One promising technology is parallel probe-based data storage, using a nanometre-scale probe to write data on a moving platform. The working principle is very similar to that of a record player applied in parallel on the nano scale. In order to access all bits on the storage medium, a nano-positioner, or scanner, is used to move the storage medium relative to the read-out probes. Several nano-positioner designs for probe data storage are found in the literature. It is not clear which actuator type (electromagnetic, electrostatic, or piezoelectric) is most suited for probe data storage. We replaced the electrodynamic actuators by comb-drives in the scanner prototype by IBM, to enable a direct comparison. e comb-drive’s areal efficiency is low, due to a relatively low electrostatic force. e comb-drive finger profile is optimized for probe data storage, for an increased shock resistance. e suitability of electromagnetic and electrostatic actuation is, among others, determined by their energy consumption.Three (partly) hypothetical scanner designs using electrodynamic, electromagnetic and electrostatic comb-drive actuators are described. Their performance is approximately equal, however electrostatic comb-drive actuation requires an order of magnitude less energy. Equations are presented for further investigations into the performance and energy consumption of the different actuation types for different file-system use cases. We succeeded in making music with MEMS structures, and named our microinstrument ‘the micronium’. Due to fabrication inaccuracies, the instrument is outof- tune and requires tuning. Besides teaching students about MEMS technology in a fun way, the micronium succeeded in presenting MEMS technology to a broad audience.

In this paper we are investigating the potential to employ small devices in crucial areas with limited volumes in electron microscopes. We present the analysis of the electric fields that are present in an electrostatically actuated micro electro mechanical systems (MEMS) device. The electric fields are modeled using finite elements methods (FEM). Preliminary results are shown from scanning electron microscope (SEM) measurements of an electrostatically actuated two degrees of freedom (2DOF) nanometer precision table. From the FEM results the influence of the electric fields on an electron beam traversing the devices can be calculated. This influence is calculated to be a trajectory displacement in the order of tens of nanometers for typical acceleration voltages. SEM measurements show significant vibrations in the images of nonmovable parts of the devices when applying actuation voltages to the devices. This shows an effect of actuation on the detected electrons while imaging. Deflections up to 2.2 μm have been observed for a voltage of 80 Vpp. This deflection cannot be fully attributed to deflections of the incoming beam. Therefore we include in a qualitative analysis the trajectory of emitted secondary electrons that are detected.

In this paper we are investigating the potential to employ small devices in crucial areas with limited volumes in electron microscopes. We present the analysis of the electric fields that are present in an electrostatically actuated micro electro mechanical systems (MEMS) device. The electric fields are modeled using finite elements methods (FEM). Preliminary results are shown from scanning electron microscope (SEM) measurements of an electrostatically actuated two degrees of freedom (2DOF) nanometer precision table. From the FEM results the influence of the electric fields on an electron beam traversing the devices can be calculated. This influence is calculated to be a trajectory displacement in the order of tens of nanometers for typical acceleration voltages. SEM measurements show significant vibrations in the images of nonmovable parts of the devices when applying actuation voltages to the devices. This shows an effect of actuation on the detected electrons while imaging. Deflections up to 2.2 μm have been observed for a voltage of 80 Vpp. This deflection cannot be fully attributed to deflections of the incoming beam. Therefore we include in a qualitative analysis the trajectory of emitted secondary electrons that are detected.

This paper describes our work to magnetically steer self-propelled devices whichmove by catalysis of hydrogen peroxide. We demonstrate manipulation of paramagnetic particles with a diameter of 100μm to a given setpoint by means of magnetic field gradients, as well as self-propelled movement of gold-platinum rods. We discuss how to reach magnetic torque control of catalytic micro motors.

In this contribution we present the compositional dependence of the longitudinal piezoelectric coefficient (d33,f), residual stress and Young's modulus of Pb(Zrx,Ti1-x)O3 (PZT) thin films. Pulsed laser deposition (PLD) was used to deposit epitaxial PZT thin films with a < 110 > preferred orientation on silicon cantilevers. By using PLD, excellent piezoelectric properties of the PZT were observed which makes it an exciting piezoelectric material for the development of actuators and highly sensitive sensors. Our investigation of the compositional distribution of the piezoelectric coefficient (d33,f) for 250 nm thick films shows a maximum value of 93 pm/V for x=0.52. The static deflection of the cantilevers, measured after the deposition of PZT thin films was used to determine the residual stress for various compositions. The observed trend in the residual stress of PZT thin films is attributed to the varying coefficient of thermal expansion for different compositions. The Young's modulus of the PZT thin films was determined by measuring the flexural resonance frequency of the cantilevers both before and after the deposition. The Young's modulus increases for the zirconium rich PZT compositions, which is in agreement with the trend observed in their bulk ceramic counterparts.

In this contribution we present the compositional dependence of the longitudinal piezoelectric coefficient (d33,f), residual stress and Young's modulus of Pb(Zrx,Ti1-x)O3 (PZT) thin films. Pulsed laser deposition (PLD) was used to deposit epitaxial PZT thin films with a < 110 > preferred orientation on silicon cantilevers. By using PLD, excellent piezoelectric properties of the PZT were observed which makes it an exciting piezoelectric material for the development of actuators and highly sensitive sensors. Our investigation of the compositional distribution of the piezoelectric coefficient (d33,f) for 250 nm thick films shows a maximum value of 93 pm/V for x=0.52. The static deflection of the cantilevers, measured after the deposition of PZT thin films was used to determine the residual stress for various compositions. The observed trend in the residual stress of PZT thin films is attributed to the varying coefficient of thermal expansion for different compositions. The Young's modulus of the PZT thin films was determined by measuring the flexural resonance frequency of the cantilevers both before and after the deposition. The Young's modulus increases for the zirconium rich PZT compositions, which is in agreement with the trend observed in their bulk ceramic counterparts.

This chapter gives an overview of probe-based data storage research over the last three decades, encompassing all aspects of a probe recording system. Following the division found in all mechanically addressed storage systems, the different subsystems (media, read/write heads, positioning, data channel, and file system) will be discussed. In the media subsection various recording media will be treated, such as polymer based, phase change, ferroelectric and magnetic. In the probe array subsection various generations of thermal probes will be discussed, as well as examples of alternative write probes using currents, electric or magnetic fields, and different principles for data detection. Special attention is paid to parallel readout of probe arrays. In the positioning section, examples will be shown of electric and magnetic scanners, either precision engineered or realized by micromachining technologies, or combinations thereof. In the systems subsection the data channel will be discussed, including the read/write electronics circuitry, data detection, and coding algorithms. Special attention is paid to the writing strategy and considerations for probe-based storage file systems.

Emerging nanotechnology-based systems encounter new non-functional requirements. This work addresses MEMS storage, an emerging technology that promises ultrahigh density and energy-efficient storage devices. We study the buffering requirement of MEMS storage in streaming applications. We show that capacity and lifetime of a MEMS device dictate the buffer size most of the time. Our study shows that trading off 10% of the optimal energy saving of a MEMS device reduces its buffer capacity by up to three orders of magnitude.

In this paper, a novel technique for fabricating Transmission Electron Microscopy (TEM) chips for investigating structural and piezoelectric properties of Pulse Laser Deposited (PLD) Lead Zirconium Titanate (PZT) thin films is presented. The method involves silicon-on-insulator (SOI) wafer technology together with deep reactive ion etching (DRIE) and highly selective etchants. This study is unique in the sense that it will facilitate in-situ characterization of the PLD PZT membranes during actuation. As well as PLD PZT, the proposed method can be applied to a variety of materials by proper selection of the etchants and tuning of the process parameters. Being a critical step of the process sequence, the deposition profile of the PZT layer on the Lanthanum Nickel Oxide (LNO) seed layer is characterized prior to fabrication. The results reveal that the PLD process is not conformal and the thickness of the LNO/PZT layer is different on surfaces with different topographies.

Emerging nanotechnology-based systems encounter new non-functional requirements. This work addresses MEMS storage, an emerging technology that promises ultrahigh density and energy-efficient storage devices. We study the buffering requirement of MEMS storage in streaming applications. We show that capacity and lifetime of a MEMS device dictate the buffer size most of the time. Our study shows that trading off 10% of the optimal energy saving of a MEMS device reduces its buffer capacity by up to three orders of magnitude.