A new type of magnetometer-accelerometer is developed with a silicon micromachining. The operation principle of the sensor is based on the well known Lorentz force caused by the interaction of a current and an external magnetic field on a suspended conducting beam. To realize a new resonant micro sensor detecting both acceleration and the geomagnetic field simultaneously, a conducting line is formed on a spring part of a silicon accelerometer having two mass plates. And a new Samsung MEMS fabrication process is developed for this sensor. The process uses a silicon-on-glass (SOG) wafer, an inverted SOG wafer, and a gold-silicon eutectic bonding for the wafer-level hermetic packaging. To operate the sensor, an ac current of its mechanical resonant frequency is driven through the conducting line. Totally 1 mW is consumed in the current driving element. This newly developed sensor is enough for the 10 degree electronic display of the orientation angle and can be used in a portable navigator such as SmartPhones and PDAs that need a small, low cost and low power electronic compass.

This paper is dedicated to the fabrication and technological aspect of a silicon microresonator sensor. The entire project includes the fabrication processes, the system modelling/simulation, and the electronic interface. The mechanical model of such resonator is presented including description of frequency stability and Hysterises behaviour of the electrostatically driven resonator. Numeric model and FEM simulations are used to simulate the system dynamic behaviour. The complete fabrication process is based on standard microelectronics technology with specific MEMS technological steps. The key steps are described: micromachining on SOI by Deep Reactive Ion Etching (DRIE), specific release processes to prevent sticking (resist and HF-vapour release process) and collective vacuum encapsulation by Silicon Direct Bonding (SDB). The complete process has been validated and prototypes have been fabricated. The ASIC was designed to interface the sensor and to control the vibration amplitude. This electronic was simulated and designed to work up to 200°C and implemented in a standard 0.6μ CMOS technology. Characterizations of sensor prototypes are done both mechanically and electrostatically. These measurements showed good agreements with theory and FEM simulations.

A prototype micro magnetic bearing actuator having an outside diameter of 2.6 mm has been fabricated at Royal Melbourne Institute of Technology and reported previously with an emphasis on fabrication issues. The discussion of this paper will focus on the design and control of the micro magnetic bearing with a particular emphasis on control system design and analysis. To this end, a simplified dynamic model for the micro actuator has been developed and used in determining controller parameters, leading to a successfully suspended non-rotating rotor in the micro magnetic bearing system.

Resonant-typed microscanners based on a silicon diaphragm and actuated by PZT was designed and fabricated on purpose to improve the deformed microstructure while resonating at high frequency. In order to yield large actuating force, hybrid PZT deposition process: sol-gel method and laser ablation was developed to manufacture thick PZT films with well-crystallized perovskite phase for the applications of microscanners. In our previous study, a sol-gel derived PZT was used due to the high film quality, large deposition area and easy composition control. However, to make a thick and crack-free PZT film, several times of coating and thermal treatment is not only time consumption, but increases the risk of contamination and leads the complicated problem of thermal residual stress. In this paper, the hybrid-derived PZT film with thickness of 3 μm was prepared with simplified steps and reduced processing time. Regarding to the performance of microscanners, 1D scan motion with straight patterns and scan angle of 8±1° has been demonstrated, while resonating with 7 Vp at resonance frequency (2325 Hz). The 2D scan pattern with area of (8±1°)×(5±1°) and less deformed edged was also obtained successfully due to the improvement of the silicon-based flat mirror surface.

Pb(Zr,Ti)O₃ piezoelectric material(PZT) has been utilized for a microactuators or microsensors. Because PZT piezoelectric materials have higher power or larger displacement than the other piezoelectric materials such as BaTiO₃. The PZT thin films were deposited onto a heated Invar alloy by using a high temperature RF magnetron sputtering. The chemical composition and the crystalline structure for deposited PZT were measured by ESCA and XRD, respectively. The chemical composition of PZT deposited stoichiometrically was almost same as the commercial based bulk PZT composition. Crystal planes (110) and (111) of PZT Perovskite structure were observed in XRD analysis. Employing over 600 degree heating, almost no pinhole on the surface was observed by SEM. Thin film actuator with 500 nm thickness has been also characterized by measuring the piezoelectric property using Laser Doppler Vibrograph. It was confirmed that the piezoelectric property has a linear relationship with the grain size, which also increased with the substrate temperature. Therefore, it is possible to control piezoelectric properties by the sizes of PZT grain, which is grown by heating substrate. The piezoelectric property of deposited PZT thin films showed a good agreement with a quoted value of bulk PZT, when the substrates were heated up at 600 degree.

Aerosol deposition method (ADM) is a high performance technique for fabricating of piezoelectric 1-100- micron- thick film on various kinds of substrate. High deposition rate (over 30 micron/min for area 5 mm × 5 mm), low process temperature (less than 600 °C) as well as micropatterning of PZT during deposition (without etching) are very attractive for MEMS, and micro-TAS applications. In this presentation, the performance of a Si diaphragm driven by PZT thick film deposited by ADM was investigated from the point of view of applications for micro-diffuser. To find optimum conditions of diffuser, 4 ~ 60-micron-thick PZT films were directly deposited onto 10 ~ 140-micron-thick Si substrate. Displacement of 65-micron-thick Si diaphragm ( 6 mm × 6 mm) driven by 14-micron-thick PZT film was 1.2 micron at 40 V ac at non-resonance frequency and was 24 micron at resonance of 22.4 kHz driven by 8 V. The influence of liquid loads on resonance frequency shift and fluidic follow were investigated as the first report.

We propose a new viscous damper using magnetically responsive fluids, whose viscous damping factor can be changed by application of a magnetic field. The used fluids are intelligent or smart fluids; MF (magnetic fluid), MR fluid (magneto-rheological fluid), and MCF (magnetic compound fluid). The damper was developed in order to avoid the sedimentation of the fluid particles and to allow the viscous damping factor to be changed by using a fluctuating magnetic field as a semi-active damper. This solves the most important problem of the previous MR fluid damper, that is, sedimentation of the particles of the fluids. We experimentally investigated the dynamic characteristics of the newly developed damper having magnetically responsive fluids. The damper is a spring and mass single-degree-of-freedom system. We dealt with the vibration in a low frequency range, less than 10Hz, for the purpose of damping in architectural applications. A comparison of the differences of the damping effects of the three kinds of the fluids, MF, MR fluid, and MCF, showed that MCF has the largest damping effect. MCF is a new intelligent fluid developed by us for the purpose of having more apparent viscosity than MF and more stable particle dispersion than MR fluid. The experimental results can be explained by the cluster of particles aggregating in the form of a chain or necklace, as observed by microscope.

Nanobioceramics based on Hydroxyapatite (HA) and its composites were synthesized using radio frequency (RF) induction suspension plasma spraying with a wet suspension as feedstock. The liquid suspension precursors were axially injected into the RF plasma at various plate powers (plasma energies), chamber pressures, probe distances and plasma gas flow rates. The processed powders varied in size according to the cyclones designed to collect the powders from medium to ultra-fine. The chamber collecting ultra-fine powder contained particles ranging from 10nm to 4μm. This study suggests that the processing parameters associated with the production of the ultra-fine powders interact in a complex manner but can be rationalised by considering the overall thermal treatment experienced by the particulates during plasma treatment.

Chemical vapor deposition (CVD) diamond has outstanding properties, including low thermal expansion, high chemical resistance and high acoustic propagation and has been widely used in optical, electrical, mechanical, chemical and thermal applications. Since synthesized diamond film results in large surface roughness, the surface treatment or polishing should be applied to expand the applications. Although reducing surface roughness by mechanical and etching methods have been investigated, the cost on the complicated equipment and on the long processing time is the most particular important issue. A new method is developed in the present study to approach the smooth surface by a catalytic grinding wheel. As grinding, the catalytic reaction occurs at the contact area between the grinding wheel and the diamond surface, and sp³ structure of diamond can be converted to sp² structure with lower bonding energy; therefore, the lower surface roughness. Consequently, the average surface roughness is extremely improved from 230 nm to 20 nm, and the processing time can be shortened 10 times more than conventional methods, either lapping, or chemical assisted lapping.

Barium strontium titanate, Ba_xSr_1-xTiO₃ (BST for short), thin films are grown on the substrates of barium magnesium tantalite, Ba(Mg_1/3Ta_2/3)O₃ (BMT for short), by pulsed laser deposition (PLD) technique. The microstructures and electric properties of Ba(Mg_1/3Ta_2/3)O₃ ceramics and Ba_xSr_1-xTiO₃ films are investigated, and the phase shifter is fabricated. Both Ba(Mg_1/3Ta_2/3)O₃ and Ba_xSr_1-xTiO₃ have perovskite structure and BMT ceramics has high Q₀ at microwave frequency , so BMT substrate is compatible and suitable for BST films. The dielectric constant and dielectric loss of the BST films are 510 and 2% respectively , and about 50% dielectric constant tunability is achieved with an electric field bias of 3v/μm. The dielectric loss of BST films shows no obvious change with the electric fields. About 50° of phase shift has obtained with an electric field bias of 2v/μm at 5GHz .

Ti-based shape memory alloy (SMA) thin films have the potential to become high performance actuator materials for microelectromechanical systems. The major challenge in fabricating Ti-based SMA thin films is composition control, since a small compositional deviation can result in very large changes in the phase transformation temperatures. Owing to extreme reactivity of titanium, oxygen contamination is a major problem during the sputter deposition of TiNi and TiNiPd SMA thin films as it alters the Ni/Ti ratio. Oxygen as a contaminant has deleterious effects both on shape memory properties and mechanical properties of these alloys. Not much work in this field has been focussed on identification, determination and elimination of oxygen contamination. Rutherford Backscattering Spectrometry (RBS)is a useful technique for accurate determination of stoichiometry and depth profiling of these alloy films. RBS is less sensitive to light elements. For this reason RBS has been complemented by Heavy Ion Elastic Recoil Detection Analysis (HIERDA) for the determination of oxygen. TiNi and TiNiPd films were deposited by DC- Magnetron Sputtering on unheated Silicon substrates by using Ti_1.08Ni_0.92 and Ti_1.08 Ni _0.74 Pd _0.18 alloy targets. RBS measurements were carried out with 2 MeV He ions whereas HIERDA used 77 MeV I¹⁰⁺ ions with a ToF-E detector. It was found that oxygen contamination is almost negligible in TiNiPd films compared to TiNi films deposited under similar conditions. Palladium is effective as a catalyst in removing the oxygen from the deposition system resulting in reduced oxygen pick-up. This paper presents the stoichiometric analysis and depth profiling of these films by RBS and HIERDA technniques

Molybdenum trioxide - tungsten trioxide (MoO₃-WO₃) and titanium oxide - molybdenum oxide (TiO₂-MoO₃) binary metal oxide thin films have been prepared by the sol-gel process and by PVD. The films were deposited using the spin coating technique and by sputtering onto alumina substrates with interdigital electrodes. MoO₃-WO₃ film morphology is composed of MoO₃ needle like grains and WO₃ spherical grains when annealed at 450°C. MoO₃-TiO₂ film morphology consists of a well-developed crystal structure for the sol-gel film and a porous morphology for the sputtered films when annealed at 800°C. The films exhibited selective gas sensing characteristics at an operating temperature of 300°C towards nitrogen dioxide (NO₂). The RF and SG fabricated MoO₃-TiO₂ possess different gas sensing properties attributed to the fabrication and resulting morphological difference of the thin films.

MOEMS micromirror device technology is becoming more important in the effort to develop cost-effective nxn optical switches for next-generation fiber optic networks. Although there are a variety of fabrication and assembly methods available, most are complex and costly. Using established flip-chip assembly techniques to perform device transfer can greatly simplify the assembly process. For this project, a high-accuracy device bonder is proposed for transfer of optical micromirror devices from one substrate to another. The same technique can be applied to individual devices, or on the wafer level. A high-accuracy device bonder was used for placement and in-situ bonding. The device bonder is capable of achieving 1 μm post-bonding accuracy in x, y and z axes. Levelling accuracy on the order of microns for a 200mm wafer ensures that the optical paths are correctly aligned. In-situ bonding also ensures that the leveling accuracy is maintained for the final device. Prior methods which use the self-levelling effect of solder bumps in a mass reflow type of operation can result in an unacceptable shift in the parallelism, ruining the device’s optical performance. Using a high-accuracy device bonder, devices can be successfully transferred using a flip-chip method. The x, y and z placement is accurate to within 1 μm and even less in some cases. The 1 μm accuracy is sufficient to ensure that optical paths align to waveguides which are subsequently used to align to a 9 μm singlemode fiber core. This method of MOEMS transfer reduces the complexity of the transfer process. Use of existing flip-chip placement and bonding techniques speeds the development cycles of MOEMS devices. The flip-chip assembly method is a cost effective and simple method for transfer of MOEMS devices. This method is enabled by a high-accuracy device bonder which is used for 1 μm accuracy placement and in-situ bonding.

A micro hot embossing process has been developed for low cost and mass-production fabrications of optical switching components. After illustrating the architecture design and mold fabrication of a proposed optical switch, this paper describes the optimizations of parameters for hot embossing process to manufacture components of the optical switch. Polycarbonate has been used as the process material. The height of embossed mirrors, the thickness of actuating cantilever and the deformation of switch platforms have been measured precisely. The influence of process parameters has been investigated, and the optimized process parameters have been recommended with the process temperature and loading force being around 180°C and 1500Kg, respectively. The design guideline of nickel mold for easier release after embossing has also been recommended. The experimental results have demonstrated technological feasibility of micro hot embossing for low cost and mass-production of micro optical devices.

Microfabrication techniques such as bulk micromachining and surface micromachining currently employed to conceive MEMS are largely derived from the standard IC and microelectronics technology. Even though many MEMS devices with integrated electronics have been achieved by using the traditional micromachining techniques, some limitations have nevertheless to be underlined: 1) these techniques are very expensive and need specific installations as well as a cleanroom environment, 2) the materials that can be used up to now are restricted to silicon and metals, 3) the manufacture of 3D parts having curved surfaces or an important numberof layers is not possible. Moreover, for some biological applications, the materials used for sensors must be compatible with human body and the actuators need to have high strain and displacement which the current silicon based MEMS do not provide. It is thus natural for the researchers to 'look' for alternative methods such as Microstereolithography (MSL) to make 3D sensors and actuators using polymeric based materials. For MSL techniques to be successful as their silicon counterparts, one has to come up with multifunctional polyers with electrical properties comparable to silicon. These multifunctional polymers should not only have a high sensing capability but also a high strain and actuation performance. A novel UV-curable polymer uniformly bonded with functionalized nanotubes was synthesized via a modified three-step in-sity polumerization. Purified multi-walled nanotubes, gained from the microwave chemical vapor deposition method, were functionalized by oxidation. The UV curable polymer was prepared from toluene diisocyanate (TDI), functionalized nanotubes, and 2-hydroxyethyl methacrylate (HEMA). The chemical bonds between -NCO groups of TDI and -OH, -COOH groups of functionalized nanotubes help for conceiving polymeric based MEMS devices. A cost effective fabrication techniques was presented using Micro Stereo Lithography and an example of a micropump was also described. The wireless concept of the device has many applications including implanted medical delivery systems, chemical and biological instruments, fluid delivery engines, pump coolants and refrigerants for local cooling of electronic components.

Micro molding and hot embossing are among the most popular techniques for fabricating microstructures in polymeric materials, due to the relatively low cost of replication. In this paper we present an investigation of a hot embossing process including the optimisation of operating parameters for polystyrene (PS) and polycarbonate (PC) substrate materials. Nickel mold inserts were made via excimer-laser ablation and Ni electrodeposition. Replication of structures, such as channels with different aspect ratios, were investigated and experimental results are discussed.

This paper reports a prototype for a standard connector between a microfluidic chip and the macro world. This prototype is the first to demonstrate a fully functioning socket for a microchip to access the outside world by means of fluids, data and energy supply, as well as providing process visibility. It has 20 channels for the input and output of liquids or gases, as well as compressed air or vacuum lines for pneumatic power lines. It also contains 42 pins for electrical signals and power. All these connections were designed in a planar configuration with linear orthogonal arrays. The vertical space was opened for optical measurement and evaluation. The die (29.1 mm x 27.5 mm x 0.9 mm) can be easily mounted and dismounted from the socket. No adhesives or solders are used at any contact points. The pressure limit for the connection of working fluids was 0.2 MPa and the current limit for the electrical connections was 1 A. This socket supports both serial and parallel processing applications. It exhibits great potential for developing microfluidic system efficiently.

The purpose of this work is to demonstrate that a novel fabrication method for 3-D microstructures (FORMULA) is applicable to fabrication of micro mechanical parts with a large flexibility. This method is a kind of layer manufacturing method of thin films for metallic or dielectric microstructures using surface-activated bonding (SAB). The bonding interfaces of thin films are investigated by transmission electron microscope (TEM). Voids were observed at the interfaces of both pure aluminum films and Al-Cu alloy films. The ratio of void on the Al-Cu/Al-Cu interface is much larger than that of Al/Al interface, although the films have the same surface roughness of 3nm in Ra (average roughness). And approximately 10nm-thick amorphous intermediate layers were found at the interfaces. Furthermore, we have fabricated a micro gear of 900μm in diameter and 200μm in height, which is about ten times as large as our previous test pieces. Overhung structures such as a bridge structure and a cantilever were also fabricated without supporting layers beneath them.

This paper reports a process used for the microfabrication of an array of hollow microneedles. The purpose of the array is for painless transdermal drug delivery. The fabrication process uses wet bulk silicon technology and copper electroplating technology. First, a microneedle array mold on <100>-oriented silicon was fabricated by wet anisotropic etching using KOH solution, then the silicon mold was electroplated with copper. After which, the hollow copper microneedle array was released by a lift-off process or by etching off the silicon mold in KOH solution. The hollow copper microneedle array has been mounted on a polycarbonate platform, which consist of laser ablated cavities and channel for external connection to drug source. In consideration of the contour of human’s skin and the geometry of the microneedle tip, which has walls of sloping gradient corresponding to the (111)-planes, the height of the microneedle array is 200 μm. Two arrays of hollow copper microneedle were fabricated. They have square base of dimensions 390 μm and 400 μm and square tips of size 100 μm and 120 μm with square holes of size 88 μm and 94 μm respectively. Both arrays have microneedle tips at 1900 μm apart from one another and consist of 10 × 10 microneedle tips.

Here, a method of preferential adsorption of dyes on micro patterned molecular monofilms is presented. Therefore, micro spot arrays consisting of different types of monofilms are exposed to dye solutions. After this immersion, the chips are rinsed in a solvent, which differentiate the desorption rate from molecular monospots and their surroundings. The degree of adsorption depends on the dye properties. Charge, polarity and H-bridges seems to play the major role in the differential adsorption. In result, the pattern of molecular monofilms can easily be identified by intensity differences of fluorescence radiation from chip surfaces.

We are developing a Scanning Beam Interference Lithography (SBIL) system. SBIL represents a new paradigm in semiconductor metrology, capable of patterning large-area linear gratings and grids with nanometer overall phase accuracy. Realizing our accuracy goal is a major challenge because the interference fringes have to be locked to a moving substrate with nanometer spatial phase errors while the period of the fringes has to be stabilized to approximately one part per million. In this paper, we present a review of the SBIL design, and report recent progress towards prototyping the first-ever SBIL tool.

Actuators made from patterned Ti-based shape memory alloy films have potential applications in micro systems owing to their high mechanical output and other favourable characteristics. Micro fabrication techniques such as chemical etching and electrolytic photo etching have been used for patterning these alloy films. The latest trend is to use laser micromachining owing to its advantages in terms of non-contact processing, achievable resolution and pattern flexibility. Successful excimer laser micromachining of TiNi in the forms of as- rolled strips (bulk) and RF Sputter deposited, free - standing foils, with different combinations of laser parameters have been recently reported. However, sufficient data pertaining to laser micromachining of these alloy films deposited on silicon substrates are required for their applications to silicon based MEMS. We have attempted to micromachine TiNi shape memory alloy films on silicon substrate deposited by DC- magnetron sputtering using a Ti₅₄Ni₄₆ alloy target. These films were micromachined by KrF excimer laser induced ablation at 248nm. The dependence of TiNi material removal mechanisms and feature quality on laser parameters such as fluence, pulse repetition frequency and number of shots are presented.

In micromachining, excimer laser ablation was a key process for producing featured by removing parts of a photoresist layer. One hurdle was that the seed layer (e.g., copper), on which the photoresist was spun, was easily attacked or damaged in laser ablation of the photoresist. To overcome this, an acoustic emission transducer (AET) was coupled to the X-Y stage of an excimer laser system to acquire surface acoustic waves (SAWs) arising from pulsed laser-material interaction. The characteristics of such a process could then be investigated by analysing this feedback AE signal. Analysis of the frequency spectrum showed that there was a dominant frequency correlating with the ablation process through one material to another. Specifically, the amplitude of the dominant frequency had an abrupt change when laser beam approached the interface of two layers. The RMS values and the variance values of raw acoustic waves were also indicative of such a process. The exact number of shots machining through one material was indicated by properly calibrating such a correlation at given laser parameters. Furthermore, the etch rate of machined material could be calculated by averaging the thickness of this material with the associated number of shots. Finally, a real-time monitoring scheme of complex laser micromachining process was addressed on the basis of taking SAWs as feedback signals.

The fabrication of microstructure with high aspect ratio is one of the most important issues in MEMS technology. This paper presents a technology of micromachining using electrochemical etching in hydrofluoric acid. Pores with high aspect ratio (>10:1) and smooth surface have been produced in the current study. The dimensions and shapes of etching pores can be varied over a wide range by adjusting electrochemical etching parameters. HF concentration is one of the most important parameter, since it influences not only etching rate but also diameter and the inner surface roughness of pores. The etching rate increases with HF concentration and so does the diameter of pores. Therefore an optimal HF concentration can be obtained. Besides, the inner surface roughness (Ra about 12nm) in 6.1% HF concentration is obtained. The roughness of different pores surface from electrochemical etching and inductively coupled plasma (ICP) etching is also compared. It is observed that pores fabricated by electrochemical etching has relatively smoother surface.

A CMOS compatible single resist layer lift-off process for forming patterns on a substrate is described. Unlike in most other methods, an ion bombardment is employed here to harden the top of the resist leaving the sidewall of the resist unaffected. The resist is then treated to a low temperature O₂ plasma etching process to achieve a T-shaped undercut profile. This process is found to be simple, repeatable and controllable. Resist profile with adjustable overhang length and the sidewalls of the resist profile with an almost T-shape could be achieved with the help of the process described in the current work. Such increased overhang length prevents metallization of the sidewalls of the resist, and thus facilitates more rapid removal of the resist during lift-off. The process starts from a patterned resist layer having vertical resist profile. It is then subjected to Ion bombardment to harden the top surface of the resist leaving the sidewalls unaffected. The ions are directed at sufficient dose and energy to cause the top of the resist mask to get hardened. Subsequently, the resist patterns are subjected to a low temperature isotropic plasma etching process resulting in an under-cut T-shaped resist profile. This process is highly suitable for MEMS application where metals like Cr, Au, Cu etc are frequently used but are difficult to dry etch.

Micromanipulation has enabled numerous technological breakthroughs in recent years, from advances in biotechnology to micro-component assembly. Micromanipulators commonly use piezoelectric actuators (PZT) and a compliant mechanism to provide fine motions with position resolution in the nanometre or even sub-nanometre range. Parallel compliant mechanisms are used to provide motion with multiple degrees-of-freedom (DOF) as parallel mechanisms provide greater rigidity and positioning accuracy than serial mechanisms. However, parallel mechanisms with multiple DOF often have dynamic behavior that is coupled, non-linear and highly complex. This leads to difficulties in modeling and controller design, often requiring sophisticated control techniques such as model-based or neural networks to provide fast, accurate control. This paper presents the findings of an experimental study into the dynamics of a particular 3 DOF compliant mechanism, specifically considering actuator-space coupling at a range of frequencies and poses. It was expected that the dynamics would be coupled as a dynamic model developed for this mechanism suggested this to be the case. However the experimental results reveal the surprising and useful finding that this mechanism possesses almost completely uncoupled dynamics for the operating bandwidth of the manipulator. This result simplifies the problem of controller design and suggests that the micromanipulator could be effectively controlled using simple independent joint control without requiring development of a decoupling controller.

In this study, nanoindents are characterized for the patterning of nanostructures. Nanoindentation is performed on Sidoped (n-type)Vertical Gradient Freeze (VGF) GaAs (100) and epitaxial GaAs (100) using a diamond Cube Corner indenter. Nanoindentation of GaAs has been studied in the past, but not at extremely low loads. Previous research has been done on high load (50-200 mN) and low load (0.2-8 mN) nanoindentation. The size of nanostructures range from 10-100 nm, requiring a nanoindentation width in the same size range. The loads required to produce such small indentations are in a lower regime of <0.2 mN, which to the authors’ knowledge is an area that has not been previously studied using a Cube Corner indenter. Ultra-low-load (<0.2 mN) nanoindentations are characterized in order to study the selective growth of nanostructures on the indentation sites. Indentations of less than 200 nm in width are produced, and mechanical properties of the two materials including hardness and elastic modulus are calculated and compared. The geometry of the indents is characterized using atomic force microscopy (AFM).

Carbon nanotubes (CNTs) are an interesting class of nanostructures which can be thought of as arising from the folding layer of graphite (a graphene sheet) to form a hollow cylinder composed of carbon hexagons. However, practical applications are still limited by the intricate process of synthesis and the inability of present day methods for large scale production of carbon nanotubes. Moreover high quality nanotubes with functionalization capability with polymers are desired for polymer MEMS, Nanodevices and BioMEMS. In this paper, an innovative CVD approacah using microwave energy was developed for large scale production of single wall and multiwall carbon nanotubes (MWNTs). Straight and helical carbon nanotubes were obtained when acetylene decomposed over the cobalt catalyst at 700°C created by microwave field. The scanning electron microscopy (SEM) of microwave driven MWNTs revealed their homogeneous nature. The high resolution electron microscopy (HRTEM) showed typical MWNT has 26 layers. The average diameter of the tubes was observed 20-30 nm. Electronc microscope observations showed higher yield of nanotubes obtained from microwave CVD than thermal filament CVD method.

The magnetic nanoparticles are fabricated in silica glass (SiO₂) using high-flux implantation of nickel negative-ions of 60 keV. Photo-absorption measurements and the cross-sectional transmission electron microscopy (XTEM) observation confirm formation of metallic Ni nanoparticles in SiO₂, and exclude possible formation of Ni silicides (Ni₃Si, Ni₂Si, NiSi) and oxides (NiO) as major products. The mean diameter of the nanoparticles was in ~2.9 nm, and the depth distribution was similar to the prediction from the TRIDYN code with taking account of the sputtering. Temperature- and field- dependences of magnetization show that the nanoparticles are in the super-paramagnetic state with a blocking temperature of ~27 K.

The construction of micro- and nano-scale electronic devices that exploit the properties of single atoms have been proposed. A very promising device is a silicon based solid state quantum computer based on an array of single ³¹P atoms as qubits in a pure ²⁸Si substrate. Operation of the device requires independent control, coupling and readout of the state of individual qubits. We have developed a construction strategy for a few qubit device based on ion implantation of the qubits into prefabricated cells. An ion energy of less than 20 keV is necessary to ensure the ion range is at the required depth in the substrate which is of the order of 20 nm. Single ion impacts are registered by the electrical transient induced in an external circuit. Electron Beam Lithography fabricated cells, containing electrodes of the required nanometre scale, have been implanted with 14 keV ³¹P ions and the pulse height spectrum of single ion impacts has been successfully recorded. Discrimination on the pulse height allows rejection of ions that suffer unacceptable straggling. This opens the way to the rapid construction of a two qubit device in the first instance that will test many of the essential mechanisms of a revolutionary solid state quantum computer.

Nanocomposite materials have attracted considerable research effort in recent years both because of their potential technological applications and because of their relevance to the study of basic physical properties in this range of sizes. On decreasing the dimensions of a material to the nanometre scale, many new effects appear, such as quantum size effects, which can result in new physical properties so that nanostructured materials can show novel optical, electrical, magnetic and catalytic properties that are different from those of bulk materials. The electrical conductivity is also related to the grain size and separation and the gas sensing properties. Many techniques can be employed to fabricate nanocomposite films, such as sol-gel, sputtering and ion implantation. In this work we have deposited mixed oxide of Mo-W, Ti-W and Mo-Ti by sputtering. The production of chemoresistive semiconducting films through selective sublimation processing Ti-W-O, Mo-W-O has been obtained and furthermore the manipulation of a metal-oxide properties by doping Mo:TiO₂ and Ti:MoO₃. This technique consists of deposition of a mixed-oxide layer, the annealing of the film leads to depletion of the phase with lowest sublimation temperature. The method allows the achievement of films ideal for gas sensing via chemoresistive effect: grain-coalescence inhibition, i.e., nanostructured materials, porous films and modifiable composition. The gas sensing properties of these materials toward gases like CO, NO₂ and ethanol have been studied.

A technique for growing single metallic nanowires through a process of field-emission from a pointed structure is described. The field-emission of electrons in the presence of metal-carbonyls results in the deposition and growth of nanowires with diameters typically ranging from 3 to 30 nm, depending on the precursor used and growth conditions. Lengths range typically from several to tens of microns. Transmission electron microscope analysis of the nanowires shows that they are overcoated with a thin (~nm) layer of carbon which prevents the oxidation and corrosion of the encapsulated wire. Tungsten, iron and cobalt nanowires have been grown from their respective carbonyls. Current-voltage measurements of tungsten nanowires show ohmic behaviour at room temperature, yielding resistivity values 11-17 times that of bulk tungsten. Tungsten wires with inner core diameters of 4-5 nm are able to withstand current densities of greater than 5×10¹¹Am^-2 before failure. Free-standing nanowires thus grown from vertically-aligned nanostructures such as carbon nanotubes can be made to contact a substrate electrode by electrostatic attraction. The technique opens up the possibility of making electrical contacts to nanostructures that are otherwise not easily contactable.

We present a double time-multiplexed interferometer based on Faraday mirrors, which can be used for two quantum cryptography channels. Two channel operation with "star" configuration, 1km + 1km telecom optical fibers, was demonstrated. Experiments show a fringe visibility of 0.96 for both channels. Crosstalk attenuation more than 70dB was observed.

We investigated the polishing effect of magnetic polishing liquid (MPL) made of abrasive particles and a newly developed magnetic responsive fluid, magnetic compound fluid (MCF) as intelligent or smart fluid. By applying steady and fluctuating magnetic fields, we investigated the polishing effects of the magnetic fields, varying the kinds of polishing material and the components of the MPL. In order to explain the cause of the experimental results, we investigated the apparent viscosity of the MCF and MPL, and used microscopic to investigate behavior of the particles in the MCF and MPL. We clarified the mechanisms governing the polishing effects through the use of a model based on the observation of the particles.

Polymerase chain reaction (PCR) microvessel, capillary electrophoresis (CE) microchannel and impedance electrodes were integrated in a monolithic biochip. This paper reports on the detailed designs and fabrications of the PCR-CE-detector integrated biochip. The CE microchannel and PCR microvessel were fabricated with PDMS poured on a master made by SU-8 photoresist. The electrode plate was integrated with Au heater and temperature sensor for PCR amplification, electrodes for CE separation and impedance detection. The structure of the microfluidic channel was introduced and the impedance of microelectrodes on the chip was simulated.

Silicon carbide based metal-oxide-semiconductor (MOS) devices are attractive for gas sensing in harsh, high temperature environments. We present a novel hydrocarbon gas sensor based on a catalytic Metal-Reactive Insulator-Silicon Carbide (MRISiC) device. This sensor has been employed as a Schottky diode. The sensor presented is capable of operating at temperatures around 600°C. It has been exposed to propene gas, which lowers the barrier height of the diode. The MRISiC devices are based on semiconducting Ga₂O₃ - ZnO thin films prepared by the sol-gel process. The thin films were deposited onto the SiC by the spin coating technique and a Pt layer was deposited on the top of the metal oxide layer forming the Schottky barrier. The sensors responses were stable and repeatable towards propene at operating temperatures between 300 and 600°C. In this paper the effect of biasing is investigated by analyzing the output voltage of the diodes when biased at constant currents of 2 and 8 mA.

Chemical vapor deposition (CVD) diamond is an emerging material in the industry. Polishing CVD diamond film to approach the mirror-like state is necessary in a lot of applications, such as optical lens, missile radome, gyrotron windows, X-ray masks, heat sink, bio-sensors, UV detectors, etc. There are several kinds of machining mechanisms existing during polishing diamond film, and they can mainly be separated into mechanical, chemical assisted and catalytic mechanisms. In the current study, the traditional mechanical polishing and chemical assisted methods are both chosen to remove the tip of CVD diamond crystal. Different grit sizes of diamond paste and strong oxidizing agents are used respectively. From the morphology of SEM, the damages after mechanical polishing and chemical assisted methods are quite different. Damages after chemical assisted polishing are much less than they after mechanical polishing. Some of the morphological evidences only show in chemical assisted polishing method. In addition, the results of the surface roughness after the two kinds of polishing methods are shown in the AFM images. Mechanical method takes longer process time than chemical assisted method to lower CVD diamond roughness. The surface roughness of diamond film is therefore from 1200nm down to 600nm after mechanical polishing; however, the roughness is from 1200nm down to 100nm after chemical assisted mechanical polishing.

Experiments performed in a reactive ion etching (RIE) system are discussed with the purpose of studying the influence of the addition of O₂ in different ratios in the main CF₄ gas flow for silicon etching. Conventional planer reactive ion etching system has been utilized for etching of SiO₂ and silicon in fluorine chemistry. The patterns were delineated in SiO₂ using photo-resist as the mask material using CHF₃ gas in combination with argon. Sidewall passivation technique has been employed to achieve microstructure profile control in silicon. The quantity of O₂ gas was varied from 2 to 10% in the total CF₄ gas flow (10 sccm) at self dc-bias of -250 volts and process pressure 30 mTorr to achieve a balance between fluorine and oxygen radicals. Anisotropic etched profiles with smooth bottom surfaces were obtained at 2% O₂ flow in CF₄. The usefulness of this technique has been demonstrated for the delineation of MEMS microstructures in silicon.

Using Aerosol Deposition Method it is possible directly deposited PZT 1~100-micron-thick films on different kinds of substrates. The mechanical, and piezoelectric properties of such piezoelectric films allowed applying it to the microactuator fabrication. In this presentation, 10-μm-thick PZT film was directly deposited on the stainless steel. After annealing and poling of PZT, the fatigue of such actuator was investigated applied bipolar electrical field of 30 kV/cm keeping actuator temperature at 100°C. After 10⁹ cycles changing in the vibration amplitude was not observed, as well as the actuator tip’s shift. Applications of such actuator for preside positioning of hard disk drive are discussed.

Samples used for the fabrication of M-S diodes were growing by Chochralski method especially undoped n-type GaP into (III) oriented wafers. The thickness and carrier concentration was 200-250 mimic and (2-4). 10 exp17 atom/cm3 respectively. At first ohmical contact to the one side of wafer was formed by alloying of indium at the temperature 600°C during 5 min in hydrogen. Then the sample with ohmical contact and wire for preceding the power was covered with chemical stable polystyrene solution except the area where the metal will be deposited. The wafers were then ached chemically, rinsed in distilled water and were transferred immediately into electrolyte. Deposition of metal was done by the usual electrochemical method. Electrolyte was poured into quartz glass. The semiconductors wafer was used as the one electrode and as another electrode was used aluminum. For deposition Al the aqueous solution of chlorides have been used as an electrolyte, which consisted also NaOCI. At first, semiconductor’s wafer was used as the anode and cleaning of semiconductors surface was done. Then the potential was immediately changed in opposite direction and deposition of metal on freshly cleaned surface was done in the same solution in a united technological process. After the process of realization the samples were washed in distilled water. The polystyrene film was removed mechanically and boiling in acetone. Then samples were cut into pieces of area 1-3 mm, and were measured electric and photoelectric characteristics. The electrical and photoelectric characteristics have been studded and they were analyzed in the usual way to calculate the ideality factor (n) and barrier height (o). The values of coefficient n and SB height were 1.05-1.07 and 1.1 eV respectively.

This paper presents approaches to fabricate Au masks for LIGA process. The proposed fabrication process starts with deposition of a thick layer of Au film, then followed by electron cyclotron resonance (ECR) Ar⁺ etching and coating of a polymer material that is used as a membrane. Finally the ICP DRIE etching is applied from backside to figure out the membrane. The profiles of the Au microstructures on the mask have been improved thanks to the optimization of etching process and photoresist material. The fabricated masks have been used in the X-ray lithography and demonstrated a well acceptable performance. A nickel mold has been successfully realized by electroplating and used in a hot embossing process for forming optical components. Au masks made by using conventional Au-electroplating technique have also been demonstrated for a comparison.

Piezoelectric materials are attractive for sensor and actuator in micro device applications, because they have the good properties capable for actuation or sensing. Recently, the piezoelectric thin film with silicon process has been widely researched in MEMS. Moreover, the bulk piezoelectric materials are being worked for accurate actuator positioner and fast actuation system. However, the microfabrication of piezoelectric materials for these applications is difficult because of ceramic materials with low etching rate. In this study, the sol-gel derived PZT thick film was etched by wet etching method. Also we fabricated the PZT film cantilever structure by the lift-off method. The silicon mold method was used for the fabrication of micro multi-layer PZT actuator. In silicon mold method, silicon wafer was etched by deep dry etching method and the etched holes in silicon wafer was filled with the PZT powder. The structure having PZT power in the silicon holes was condensed using the hot isostatic pressing (HIP) sintering method for micro multi-layer PZT/silicon actuator.

We have fabricated micro carbon rod/needle structures of size 30 to 400 μm on graphite substrate by the pyrolytic decomposition of ethylene precursor gas using argon ion laser (514.5 nm) at different laser power and chamber pressure. The micro carbon rods were characterized using Raman spectroscopy and two broad peaks centered at 1320-1345 cm^-1 and 1589-1602 cm^-1 were observed, which corresponds to D (disorder) and G (graphitic) bands, respectively. LCVD grown micro carbon rods consists of highly polycrystalline graphite as well as amorphous carbon phase. The microstructural features of the LCVD grown micro carbon rods are discussed in detail.

The Resonant tunneling diode (RTD) is a high speed nanoelectronic device based on quantum resonant tunneling effect. It has the advantage of high frequency, low operating Voltage, low power dissipation, negative resistance, bistability and self-latching. It can be applied in high speed integrated circuits widely. Based on the analysis of correlation between the device characteristic parameters and the material structure parameters, some design rules have been summarized as following: 1. The barrier width L_B of RTD should be selected as narrow as possible to increase the peak current density J_p. 2. The well width L_W should be selected slightly wider to decrease the peak Voltage V_p. 3. The spacer width L_S should be selected slightly narrower to decrease the peak Voltage V_p. 4. The emitter doping density N_E should be determined to a reasonable value to avoid both R_S and intrinsic capacitance C_d too much. 5. Selecting AlAs as the barrier material to increase the barrier height then to increase peak valley current ratio (PVCR). 6. In emitter region, adding a narrow bandgap material layer to form a subwell. The 3dimension/2dimension resonant tunneling changes to 2dimension/3dimension resonant tunneling, the PVCR will be improved. From above design rules, The GaAs based MBE material structure of RTD has been designed, The RTD devices have been fabricated from this material structure shown very good performance. Main characteristic parameters listed as following: Room temperature PVCR 7.6, f_R=54GHZ, switching time t_r≈171ps.

This paper discusses the development of position sensors for mechatronic applications. In particular, these sensors were developed for magnetic bearings which require position sensing of the rotor relative to the stator. Magnetic beaings are open loop unstable, and therefore, require closed loop control of rotor position to centrally position the rotor relative to the circular bearing stator. Therefore, the position sensors are required to have high sensitivities and good resolution. In addition, electro magnetic interference (EMI) rejection and drift need to be taken into account in designing or selecting sensors for magnetic bearings, as often the magnetic bearing is operating in an environment of strong electro magnetic fields. This paper discusses displacement measuring sensor system types and the performance of units developed for high speed rotating systems and micro-scale units for mm scale magnetic bearings. The reasons to choose a particular type of sensor are discussed and the performance of inductive sensors in particular are presented. The discussion will also focus on properties of sensing coils and signal conditioners for macro as well as micro magnetic bearings.

The proper exchange of automobile engine oil leads to the saving of resources as well as the safe maintenance of automobile engine. In this paper, we designed the capacitive sensor to monitor changes in the dielectric constant of the engine oil and we fabricated the sensor by using semiconductor fabrication technology. Experiments have been carried out with the fabricated sensor equipped on oil chamber using a typical fully-formulated oil. The capacitance of sensor increased at about 3 percent per 1,000km.

The work function of tin oxide has been studied by the kelvin probe method as a function of the exposure to different gaseous species. Characterisation has been performed in dark and in presence of sub band and supra band gap light (Surface Photovoltage measurements). The light changes the response towards gases in particular at room temperature. The results foresee the possibility to improve semiconductor sensor selectivity by using monochromatic light at well defined frequency able to activate/deactivate surface states where species are adsorbed.

Preparation of hard magnetic SmCo thin films onto silicon substrate has been considered as one of the important steps in the realisation of magnetic MEMS devices. In this paper, we report the results of our investigations on the deposition and characterisation of these films. In particular, this paper deals with the study of the effect of argon gas pressure (10 ~ 40 mTorr) and substrate temperature (R.T. ~ 600 °C) on the composition, structure, and magnetic properties of SmCo thin films. These films were characterised using RBS, XRD and SQUID. The results indicate that the Co/Sm ratio of the films decreases with increasing argon gas pressure, but increases with increasing substrate temperature. As substrate temperature rises, both the degree of crystallinity and in-plane texturing increase, resulting in an increased in-plane intrinsic coercivity. Films prepared at lower substrate temperatures exhibit lower coercivity values due to the amorphous or partially crystallised phases in the films.

This paper presents the results of our investigations on excimer laser micromachining of SmCo thin films. These films were prepared onto silicon substrate with a SiO₂ layer and chromium film on the top. The ablation characteristics of the films were analysed by examining the surface topography using optical microscopy and Scanning Electron Spectroscopy (SEM). The quality of the etched patterns was evaluated in terms of sharpness of the edges, side wall profile and ratio of pattern mask size to feature size. The etch characteristics were studied over a wide range of laser parameters with the fluence in the range 0.25 J/cm² and 1.6 J/cm² and the number of shots varied from 1 to 50. The results showed that the precise nature of the resulting structure is a strong function of fluence and number of shots. These studies provide insight into the ablation behaviour of SmCo films and their potential applications in MEMS.

The NSF-EC Workshop on Nanomanufacturing and Processing was held in San Juan, Puerto Rico on 5-7 January 2002. The Workshop was held within the framework of the cooperation between the National Science Foundation (NSF) and the European Commission (EC, materials sciences), with the aim of catalyzing progress in research and education in the emerging field of Nanomanufacturing and processing. It is envisioned that this NSF-EC cooperation will provide a critical thrust to translate the growing global investments in the field of Nanoscale Science and Engineering into new scientific developments and engineering applications that will have a mutually beneficial impact for both the U.S. and European research partners and broader societies.

The Jet Propulsion Laboratory (JPL) has developed a novel nanometer-thick “Soft Ionization Membrane” (SIM) which is capable of ionizing nearly 100% of the gases that pass through it. Both sides of the membrane are coated with a metallic conducting film. A modest potential of less than 10 Volts across the membrane produces an electric field in excess of 10⁷ V/cm over a region that is smaller than the mean free path of gas molecules which ionizes the neutral molecules that passing through. Because the region of high electric field is smaller than the mean free path of gas molecules, there are virtually no high energy collisions and the system does not suffer from the fatal problem of avalanche breakdown. The soft ionization mechanism does not fracture the medium or cause any secondary ionization. Thus, a truly new ionization technique is enabled by a simple nanoscale micromachined device. The SIM is tiny, rugged and well suited for a wide variety of applications ranging from space micropropulsion systems to miniature analytical separation devices. In this paper we focus our attention on ion mobility spectrometers (IMSs) as a potential candidate to be incorporated with SIM.

Knowledge of the mechanical behavior of strategically important materials such as silicon at nano scale is the key for building next generation devices. In this paper, we investigate the Young’s Modulus of nanomechanical beams [1-8 mm long, 200-400 nm wide, and 193 & 255 nm in thickness] fabricated from silicon-on-insulator (SOI) wafers. The beams of different dimensions were defined in PMMA resist using e-beam lithography. A layer of chrome deposited using lift-off technique, acted as an etch-mask for silicon to fabricate the beams by using RIE. The samples were dipped in BOE (Buffered Oxide Etch) to etch the oxide underneath and the beams were released using critical point drying. Using a Scanning Probe System, nanomechanical beams were bent using AFM silicon tapping mode probes. A controlled amount of force was applied by varying the voltage applied to the Z-axis piezoactuator. The values of beam deflection and the net force applied enabled us to plot the Load vs. Displacement graph for the bending of the nanomechanical beams. Using Euler - Bernoulli beam bending equations, the Young’s Modulus of the <100> Silicon beams was measured to be 174 GPa. This value agrees within 5% of the known value of bulk silicon Young’s modulus of 169GPa. Thus we conclude that the value of Young’s modulus of <100> Si beams does not change when the size is reduced to nanometer regime.

It is possible to have two games that are losing when played in isolation but that, because of some form of feedback, produce a winning game when played alternately or even in a random mixture. This effect is known as Parrondo's paradox. Quantum mechanics provides novel methods of combining two games through interference and entanglement. Two models of quantum Parrondo's games have been published and these are reviewed here. We speculate on a model of a quantum Parrondo's game using entanglement. Such games could find a use in the development of algorithms for quantum computers.

The development of a novel Ionic Conductive Polymer Film (ICPF) micro actuator is presented in this paper. A commercial solution from Dupont Co. (Nafion SE-5012) was used to prepare ~0.2μm thick ionic conductive polymer film. Cantilever structures composed of Au/Nafion/Au film layers were microfabricated on silicon substrate based on photolithographic technique. The structure was released by etching sacrificial aluminum in phosphoric acid at room temperature. The smallest actuators fabricated were 200μm wide, 400μm long and 0.2μm thick. We have proved that these actuators could be fully actuated in water at ~3V DC voltages. In addition, another interesting actuation behavior of the micro actuator was observed during fabrication. The actuators tended to curl whenever contacted with water during sacrificial release process. The process reversed instantaneously with the immersion in acid. We suggest that this phenomenon is due to the different volume expansion of Nafion in different medium. We are currently studying the consistency of the actuation behaviors. In the future, the design of the structures will be modified to realize precise control of actuation behavior and practical applications.

This paper describes development of the modular microfluidic components and their integration, directed toward the development of an electrochemical immunoassay-based bio-chemical detection system. The entire system consists of an array of fluid reservoirs, microfluidic valves & pump, a sampling/reaction chamber with integrated electromagnetic filterless bio-separator and a detection chamber comprising of the filterless bio-separator and an immunosensor. The magnetic beads are used to capture and detect the target toxins/molecules. This paper discusses the performance of the fluidic components and presents the preliminary results and packaging aspects of the 1st generation fluidic system. The effect of component size on system performance is also discussed.

The paper reports on the development of low temperature silicon-to-glass anodic bonding for wafer level microelectromechanical systems (MEMS) packaging. A hydrogen-free amorphous silicon layer of about 40 nm thickness was deposited on the silicon substrate. The effects of bonding temperature and voltage on the bond integrity and strength were investigated. The bonding temperatures and voltages ranged from 200 to 300 °C and 200 to 1000 V, respectively. It is found that bubble-free interface can be achieved as long as the temperature is above 250 °C. Even at lower temperatures, the unbonded area can be less than 0.5% of the wafer area. The bubble size decreases with an increase in the bonding temperature. A similar effect was observed with the applied voltage. The bond strength obtained was typically 20 MPa or higher. In the destructive tests, fractures were found to occur mainly inside the glass wafer rather than at the interface. The interface was analysed with Raman spectroscopy and SIMS. The analyses showed that Si-O chemical bonds are formed at the interface. Higher bonding temperatures result in more oxygen migrating to the interface and reacting with Si to form Si-O bonds. Electrostatic attraction and chemical reaction are the two main mechanisms that generate the bonding between silicon and glass wafers.

This report describes the strategy after the Micromachine Research and Development project. The proposal was made in a committee meeting primary attended by members of the Micromachine Center that was held last fiscal year. It is concluded that the combination of NANOstructures on MICROsystems (NANO-ON-MICRO) plays a very important role for nanotechnology as well as conventional manufacturing technology. To promote this strategic approach, the action taken immediately is mentioned as three in one: infrastructure, consulting service and grant for innovative ideas. The innovative ideas are surely appearing from the promising area of manufacturing, e.g. multimaterial MEMS/NEMS, 3D MEMS/NEMS, micro/nanomanipulation, and design/simulation.