DC/DC converters are widely used in consumer electronic devices where usually a single power source is available while the electronic board of the device requires different voltage levels in order to power-up different block functions. In this paper we present the design of a MEMS single-input multi-output voltage level shifter. The low-voltage to high-voltage conversion is based on the electrostatic transduction of variable capacitors built using interdigitated comb fingers. A 1 mm2 MEMS prototype has been designed and fabricated using the SOIMUMPs process. In this study we present the co-design and co-simulation of the whole system (the MEMS device and its dedicated charge-pump-circuit) in a single EDA environment through MEMS+ (a Coventorware® tool that allows the co-simulation of MEMS and electronics in the Cadence Analog Design Environment). We present analytical, FEM and MEMS+ models of the multi-output DC–DC converter and show that all our models converge towards the experimental results.

DC/DC converters are widely used in consumer electronic devices where usually a single power source is available while the electronic board of the device requires different voltage levels in order to power-up different block functions. In this paper we present the design of a MEMS single-input multi-output voltage level shifter. The low-voltage to high-voltage conversion is based on the electrostatic transduction of variable capacitors built using interdigitated comb fingers. A 1mm2 MEMS prototype has been designed and fabricated using the SOIMUMPs process. In this study we present the co-design and co-simulation of the whole system (the MEMS device and its dedicated charge-pump-circuit) in a single EDA environment through MEMS+ [a Coventorware® tool that allows the co-simulation of MEMS and electronics in the Cadence Analog Design Environment]. We present analytical, FEM and MEMS+ models of the multi-output DC-DC converter and show that all our models converge towards the experimental results.

This paper presents the development of a monolithic CMOS-MEMS platform under the iDesign and SemeMEMS projects with the aim of jointly providing an open access “one-stop-shop” design and prototyping facility for integrated CMOS-MEMS. This work addresses the implementation of a 3-axis accelerometer and a pressure sensor using Semefab’s in-house 2-poly 1-metal CMOS process on a 380/4/15 μm SOI wafer; the membrane and the proof mass being micromachined using double-sided Deep Reactive Ion Etching (DRIE). This monolithic approach promises, in high volume production and using low complexity processes, a dramatic cost reduction over hybrid sensors. Furthermore, the embedded signal conditioning and the low-noise level in polysilicon gauges enables high performance to be achieved by implementing dedicated on-chip amplification and filtering circuitry.

Fault-tolerance is an important design requirement in critical sensor applications. It is conventionally achieved by using redundant components, which increases system's size, cost and complexity, that are often sacrificed or comprised due to associated limitations. This paper proposes a novel solution to achieve sensor fault-tolerance at the system level instead of the usual approach that targets the component level. The architecture consists of multi-functional sensors which are used to replace conventional single mode sensors, and a data fusion algorithm which provides online test and fault-tolerance. This method has the potential to significantly increase system reliability and supports a reduction in the overheads inherent with the use of redundancy in fault-tolerant systems. A MEMS humidity/pressure sensor has been designed as an example to support the method. The sensor has simple structure, good linearity and sensitivity, and the potential of further integrating a temperature function.

Aluminium nitride (AlN) is a thin film piezoelectric material having excellent potential for integration with microelectronic systems. We have investigated flexural modes of Si3N4 membrane structures with and without an AlN active layer. AlN films typically 3 μm thick were deposited by RF sputtering. Mechanical excitation was provided acoustically by sweeping the excitation frequency of a 1 MHz air-coupled ultrasonic transducer. Mode shapes were verified by scanning laser vibrometry up to the [3,3] mode, in the frequency range 100 kHz to 1 MHz. Resonant frequencies were identified at the predicted values provided the tension in the layers could be estimated. For a membrane structure incorporating an AlN layer, acoustic and electrical excitation of flexural modes was confirmed by displacement measurements using laser vibrometry and resonant frequencies were compared with analytical calculations.

Health and usage monitoring as a technique for online test, diagnosis or prognosis of structures and systems has evolved as a key technology for future critical systems. The technology, often refereed to as HUMS is usually based around sensors that must be more reliable than the system or structure they are monitoring. This paper proposes a fault tolerant sensor architecture and demonstrates the feasibility of realising this architecture through the design of a dual mode humidity/pressure MEMS sensor with an integrated temperature function. The sensor has a simple structure, good linearity and sensitivity, and the potential for implementation of built-in-self-test features. We also propose a re-configurable sensor network based on the multi-functional sensor concept that supports both Normal Operational and Fail Safe Modes. The architecture has the potential to significantly increase system reliability and supports a reduction in the number of sensors required in future HUMS devices. The technique has potential in a wide range of applications, especially within wireless sensor networks.

This paper presents the development of a monolithic CMOS-MEMS platform under the iDesign and SemeMEMS projects with the aim of jointly providing an open access “one-stop-shop” design and prototyping facility for integrated CMOS-MEMS. This work addresses the implementation of a 3-axis accelerometer and a pressure sensor using Semefab’s in-house 2-poly 1-metal CMOS process on a 380/4/15μm SOI wafer; the membrane and the proof mass being micromachined using double-sided DRIE. This monolithic approach promises, in high volume production and using low complexity processes, a dramatic cost reduction over hybrid sensors. Furthermore, the embedded signal conditioning and the low-noise level in polysilicon gauges enables high performance to be achieved by implementing dedicated on-chip amplification and filtering circuitry.

Health and usage monitoring (HUMS) as a technique for online test, diagnosis or prognosis of structures and systems has evolved as a key technology for future critical systems. The application of HUMS technology requires a portfolio of reliable miniaturized sensors, capable of delivering "intelligence" on the internal and external environment of a system or structure. This paper proposes a fault tolerant sensor architecture and demonstrates the feasibility of realising this architecture through the design of a dual mode humidity/pressure MEMS sensor with an integrated temperature function. The sensor has a simple structure, good linearity and sensitivity, and the potential for implementation of built-in Self-test features. We also propose a re-configurable sensor network based on the multi-functional sensor concept that supports both normal operational and fail safe modes. The architecture has the potential to significantly increase system reliability and supports a reduction in the number of sensors required in future HUMS devices. The technique has potential in a wide range of applications, especially within wireless sensor networks.

Most mechanical properties of micro/nano materials cannot be determined using purely theoretical approaches or by extrapolation from bulk measurements. These properties are usually extracted experimentally by using micromechanical test structures such as cantilevers. This paper reports a novel cross-shaped structure used to simultaneously extract the Young's modulus and Poisson's ratio using the force-deflection principle. Equations for calculating the Young's modulus and Poisson's ratio are derived, and using these, an experimental demonstration of this method is presented. The average values of the Young's modulus and Poisson's ratio for the device layer commercially sourced silicon on a silicon-on-insulator (SOI) wafer are measured to be 116.5 +/- 2.24 GPa and 0.32 +/- 0.03, respectively.

We present a two-staged BCB- and anodic-bonding-based packaging approach used to package both a 3-axis piezoresistive accelerometer and an absolute pressure sensor both based on the same CMOS/SOI process with integrated on-chip amplification. A number of electrical connections run from the sensing element and the integrated amplification circuitry to the bond-pads, crossing the area used for the bond. Therefore, the bonding technique used for the top surface needs to provide good conformance over non-planar structures in order to create a sealed cavity. Zero-level packaging is achieved using anodic bonding of a pyrex wafer on the back-side and a BCB-based bonding approach to attach another pyrex wafer to the front-side. As the seismic mass of the accelerometer is formed by both the SOI-handle and -device layers, recesses to allow upwards and downwards movement of the mass are crucial for the performance of this device. Due to the heat-induced reflow process and the relative softness of the BCB material good conformance over non-planar connection tracks is achieved in the bonding process.

Micro-scanners have been widely used in many optical applications. The micro-scanner presented in this paper uses multimorph-type bending actuators to tilt a square plate mirror. This paper presents a complete analytical model of the piezoelectric micro-scanner. This theoretical model based on strength of material equations calculates the force generated by the multimorphs on the mirror, the profile of the structure and the angular deflection of the mirror. The proposed model, used to optimize the design of the piezoelectric silicon microscanner, is intended for further HDL integration, allowing in this way system level simulation and optimization.

Micromirrors based on Micromechanical. systems (MEMS) have been essential components in many applications, such as micro confocal microscopy, optical data storage and biomedical imaging [1-3]. A variety of microfabrication and actuation technologies have been used to realize micromirrors, including electrothermal [3], electrostatic [1], etc., of which electrostatic torsional drive ha s been thought to be the most popular driving mechanism. K. E. Peterson [4] has developed the world first 1-D electrostatic driven torsional micromirror. The Lucent [5] Lambdroutor is one of famous and successful examples of 2-D electrostatic torsional micromirrors. For design improvement of this type of 2-D micromirror, Toshiyoshi et al. [6] have proposed a linearization method based on applying a small control voltage over a large bias voltage. Chiou et al. [7] have presented improved design to demonstrate linear stepping angles of 1-D micromirrors based on multiple electrodes. These developments are focus on realizing linear steps in angle. As mentioned by above articles, there are also displacements in z-axis as the micromirror is actuated, which have been ignored. The z-axis displacements have become a significant problem when the micromirrors are used on high resolution spatial scanning. Krishnamoorthy et al. [8] presents a dual-mode 1-D micromirror utilizing stacked multilayer vertical comb drive actuators, which can provide both piston and tilt motion. We have developed a z-axis displacement compensation concept for 2-D electrostatic torsional micromirrors previously [9].

This paper discusses the design of an integrated monolithic 3-axis piezoresistive accelerometer on SOI.

This paper concerns the modeling of a piezoelectric micro-scanner. The micro-scanner presented in this paper uses multimorph-type bending actuators to tilt a square plate mirror. A complete analytical model of the piezoelectric micro-scanner is presented. Each step of the modeling has been validated by Finite Element Modeling. This theoretical model based on strength of material equations calculates the force generated by the multimorphs on the mirror, the profile of the structure and the angular deflection of the mirror. The proposed model, used to optimize the design of the piezoelectric silicon micro-scanner, is intended for further HDL integration, thereby allowing rapid system level simulation and optimization.

Orogenic gold-bearing quartz veins in the middle Tertiary Bullendale Fault Zone, New Zealand were mined historically for coarse gold in a narrow zone (ca. 5 m thick). However, recent drilling has revealed a broad hydrothermal alteration zone extending into the host schist, in which disseminated sulphide and gold mineralisation has occurred. The evidence of alteration is first seen over 150 m across strike from the fault zone, and the best-developed alteration halo is about 50 m wide. The extent and intensity of alteration is strongly controlled by local structures that developed during regional Tertiary kink folding of the pervasively foliated and fissile metasedimentary schist host. The earliest structures are foliation-parallel microshears (micron to millimeter scale) formed during flexural-slip folding. Later, but related, structures are predominantly normal faults and associated shear zones that have formed extensional sites during the regional folding event. All these structures facilitated hydrothermal fluid penetration and rock alteration, with localised vein formation and brecciation. Where fluid has followed structures, metamorphic chlorite, phengite, and titanite have been altered to hydrothermal ankerite, rutile, and muscovite or kaolinite. Ankerite with Fe/(Fe+Mg) <0.4 formed in host rocks with Fe/(Fe+Mg) of 0.6, and iron released by ankerite alteration possibly formed pyrite and arsenopyrite that host disseminated gold. Fault zones were extensively silicified and veined with quartz, albite, sulphides, and gold. Host rocks have wide compositional variations because of centimeter-scale metamorphic segregation. However, the alteration halo is characterised by elevated CO2 and S, as measured by loss-on-ignition (doubled to ca. 6 wt.%), elevated As (100–10,000 ppm), and weakly elevated Sb (up to 14 ppm). Strontium is elevated and Ba depleted in many altered rocks, so Sr/Ba ratio increases from <1 (host rocks) to >3 in the most altered and silicified rocks. Many altered and mineralised rocks have low Sr/Ba (<0.5) as well. The subtle geochemical signature is not useful as a vector to ore because of the strong microstructural control on alteration. Likewise, there is no evidence for spatial mineralogical zonation across the alteration halo, although the most intense alteration is centred on the main fault zone, and intensity of alteration is controlled by microstructures at all scales. As documented in previous studies, hydrothermal alteration haloes enlarge the exploration target for some orogenic gold deposits, and may include disseminated gold, as in this Bullendale example.

A novel design of a MEMS DC/DC converter that has single input and two outputs based on the tunable capacitor principle is reported. The multiple-output has been achieved by designing comb finger pairs with different gaps located in the same structure. The device prototype has been designed and fabricated by SOIMUMPs, which is I x I mm in size. Measurement results show that it takes around 50 ms for the convener to convert a 5 V signal to two different voltages simultaneously, which are 9 and 6.8 V, respectively.

This paper reports on the design, simulation and opto-electro-mechanical characterization of a microelectromechanical system (MEMS) scanner actuated by an out-of-plane ( vertical) electrothermal actuator that was fabricated using a single layer silicon-on-insulator (SOI) foundry process. The overall size of the scanner, including the micromirror and the actuator, is 2 mm x 1 mm. A maximum static mechanical tilting angle of 5 degrees is achieved at a dc driving voltage of 18 V and current of 23 mA, corresponding to a 10 degrees optical scan angle. The scanner can be operated from dc to low frequencies ( the 3 dB bandwidth is from 0 Hz to 80 Hz), which meets the requirement for certain practical opto-electronic systems such as optical coherence tomography (OCT) systems. The scanner has a maximum mechanical tilting angle of 8 degrees at its resonant frequency of 2.19 kHz, corresponding to a total of 16 degrees maximum optical scan angle. Simulations of static and dynamic performances of the scanner have been conducted using finite element method (FEM) software, resulting in outcomes similar to the experimental findings. A thermal response time of 60 ms is calculated numerically using heat flow theory, while a thermal response time of 55.6 ms was experimentally obtained by analysing the intensity distribution of the scanned patterns generated when using a square driving waveform to drive the scanner.

Adaptive antenna technology represents the most advanced smart antenna approach to date. Using a variety of new signal-processing algorithms, the adaptive system takes advantage of its ability to effectively locate and track various types of signals to dynamically minimize interference and maximize intended signal reception. This paper presents the design and development of a micro-antenna for SoC, working at 43.763 GHz and controlled by independent MEMS based DMTL phase shifters which are low power in nature. We have also explored other required low power SoC devices which would also have the ability to reconfigure to the demands of our communication device. This in turn will enhance the desirability of our adaptive antenna for future low power mobile devices. The criteria for such a device must be its small size, a functionality that must make it possible to use over a wide variety of applications and similar fabrication techniques as with the rest of the SoC design. Our MEMS based design allows us to have all the communication and control circuitry on a single silicon substrate; enabling easy fabrication

We report a new method for maintaining constant z-axis displacement of an electrostatic torsional micromirror driven by quadrant electrodes, by adding an additional control electrode. The voltage applied to the control electrode is theoretically related to the voltages applied to the quadrant electrodes. The mathematical model is presented and validated through finite-element analysis.