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This paper presents a pair of trapezoid microcantilever probes with a monolithic micromachined thermocouple for inspecting the electrical and thermal properties of Micro-LED. To meet testing requirements, one of the microcantilevers was designed as a single-layer Ni structure for electrical conduction, while the other one, which consists of n-type poly-Si, SiO₂ and Ni layers, was used for temperature sensing. Both microcantilevers were fabricated by using Si bulk micromachining, thin film deposition, and electroplating processes. Fabrication result shows the length of each probe is about 78 μm and 118 μm, and the thicknesses of the microcantilevers and probe tip are 7.2 μm and 5.5 μm. Experiment results depict that the thermocouple junction between Ni layer and poly-Si achieves a good ohmic contact, and the measured sheet resistances for poly-Si and electroplated Ni are 150 Ω /sq and 0.01 Ω /sq. This suggests that the induced thermoelectric voltage can be generated and detected in response to a temperature difference. Mechanical tests verified that the probes provide an available elastic deflection to guarantee that the probe tips can exactly contact the Micro-LED electrodes, with a low contact force. The thermoelectric characteristics of the device have been further confirmed and calibrated on the basis of the measurement results of a commercial mm-sized LED in cooperation with an infrared camera. For the subject of the Micro-LED chip with a square size of 75 μm, its electrical and thermal properties were successfully determined, as the measured chip temperature is 52 °C at the applied current of 100 μA. [2021-0053]

This study presents the design and implementation of a MEMS capacitive tactile force sensor with polydimethylsiloxane (PDMS) filler for in-process and in-use modulation of the sensing range and sensitivity performance. The presented MEMS tactile force sensor consists of a loading unit with driving electrodes, PDMS filler, and a sensing unit. By varying input voltages on the driving electrodes (either in curing process or in-use), the stiffness of the PDMS filler as well as the loading unit can be modulated. Thus, the sensitivity and sensing range of the presented tactile force sensor was modulated accordingly. Since each sensor has its own driving electrodes and electrical routings, different input voltages can be applied to modulate the PDMS for each individual sensor. As a result, tactile sensors of different sensitivities and sensing ranges can be simultaneously fabricated and monolithically integrated on the same chip using the presented approach. The tactile sensors were implemented using TSMC $0.18~\mu \text{m}$ 1P6M standard CMOS process together with the in-house post-CMOS releasing and the polymer filling processes. Experiments demonstrate the capabilities of implementing various tactile sensors with different sensing ranges and sensitivities on a single chip by the in-process and in-use modulation techniques. Through the in-process and in-use modulation, the presented CMOS-MEMS tactile sensors show the sensing window: (1) for sensitivity modulation: 8.6 fF/N to 219.1 fF/N, and (2) for sensing range modulation: 30 mN to 270 mN.

This article proposed a novel design for the monolithic micro-LED array, directly integrated with a sapphire microreflector. Its resolution was 300 dpi. Theoretically, each micro-LED pixel owns an individual sapphire microreflector which can directly concentrate rays from an emitting source. Therefore, this study proposed that the optical crosstalk between neighboring micro-LED pixels could be suppressed and the contrast of the micro-LED array improved; as this would be especially beneficial for display. The simulation results showed that the increased thickness of the sapphire microreflector could further improve the optical performance of the micro-LED array. For the fabrication process, the key technology was an integrated process involving the inductively coupled plasma (ICP) etching technology for sapphire and micro-LED fabrication, which was used to fulfill the proposed and reference micro-LED arrays. The measurement results showed that the sapphire microreflector could effectively concentrate the emitting rays and increase the contrast of the micro-LED array. In addition, it also indicated that the inclination angle of the microreflector could further improve optical performance. Therefore, this approach was verified to be capable of improving the performance of the micro-LED display.

This study demonstrates the integration of thermoelectric type MEMS infrared (IR) sensor with plasmonic metamaterial absorber (PMA) through a standard CMOS process platform to improve the responsivity of MEMS IR sensor in a specific range of wavelength. Based on an existing thermoelectric IR sensor with the serpentine film structure, the proposed device further combines with a Metal-Insulator-Metal (MIM) type PMA. The absorber consists of a top antenna layer, a middle dielectric spacer, and a bottom reflector, and the metal and dielectric films in the standard CMOS process are exploited in this study to implement the MIM design. The advantage of narrow linewidth in CMOS process can meet the need of critical dimensions for MIM antennas. The absorption wavelength can be adjusted by varying the pattern and dimension of antennas. The MIM PMAs are designed in the coupling regime, and hence the shifting of absorbed wavelength caused by the variation of antenna dimensions from fabrication can be prevented. The feasibility of the presented MIM PMA is demonstrated by simulations and experiments. The absorption spectra measured by FTIR show the capability of proposed MIM PMAs in extending the absorption range of far-infrared. Measurement results also indicate that under the same sensor footprint and the equal number of thermocouples, the device integrated with the proposed MIM PMA has a 20 percent improvement in responsivity as well as detectivity.

This study presents a backside loading design inductive tactile sensor with the monolithic integration of thermometer. Based on the commercially available standard complementary metal-oxide-semiconductor (CMOS) process (the TSMC $0.35\mu \text{m}$ 2P4M CMOS process) and the in-house post CMOS processes, the sensing chip is designed and implemented. The electrical connection is further achieved by using the flip-chip bonding process, and hence the breakage of bonding wires by the tactile load can be avoided. The CMOS sensing chip consists of the magnetic sensing coil and the polysilicon RTD (resistive thermal detector). Moreover, a cavity is defined on the backside (silicon substrate) of CMOS chip to act as a mold for the polymer filler as well as the housing for the chrome steel ball contact interface. The tactile force will cause the polymer deformation and chrome steel ball displacement, and further lead to the magnetic flux change on the sensing coil. Thus, the tactile force is detected by the inductance variation of magnetic sensing coil on the CMOS chip. Moreover, the temperature variation is detected by the resistance change of RTD thermometer, and the in-situ temperature monitoring during tactile loading is achieved. The force response of the proposed tactile sensor and the temperature response of the thermometer have been characterized. The influence of temperature variation on the tactile sensor has also been calibrated. Moreover, the characteristics of the thermometer on sensing chip at different contact conditions are also investigated.

This letter presents a simple approach to implement the inductive-type micro tri-axial tactile sensor by integrating a complementary metal–oxide–semiconductor (CMOS) chip with sensing coils and a stainless steel sheet (as the sensing interface) using polymer encapsulation. In addition to the component integration, the polymer layer is exploited as the spring for the tactile sensor. The proposed CMOS-MEMS inductive tri-axial tactile sensor presents several features and advantages as follows: 1) the gap-closing inductive sensing approach is used for normal force ( ${Z}$ -axis) detection; 2) the area-change inductive sensing method is adopted for shear forces’ ( ${X}$ -axis and ${Y}$ -axis) detection; 3) the compact sensing coil array is implemented using the standard CMOS process; and 4) the polymer is employed as the encapsulation layer to cover and integrate the rigid stainless steel sheet sensing interface and the CMOS chip, while also acting as the spring to avoid the fragile suspended thin-film structure. To demonstrate the concept, a CMOS sensing chip with a $2\times 2$ coil array is fabricated using the Taiwan Semiconductor Manufacturing Company standard process and is further integrated with a stainless steel sheet prepared by laser machining. The measurements indicate that the typical fabricated tri-axial inductive tactile sensor exhibits a normal load sensitivity ( ${Z}$ -axis) of 2.9 nH/N, an ${X}$ -axis shear force sensitivity of 17.4 nH/N, and a ${Y}$ -axis shear force sensitivity of 15.3 nH/N.

A complementary metal–oxide–semiconduc-tor (CMOS)–microelectromechanical system (MEMS) accelero-meter with stacked pure oxide layers as mechanical structures was developed. Metal layers were confined to the sensing electrodes and electrical routings; the metal–oxide composite in the CMOS–MEMS accelerometer was distributed in limited regions. This design has two major advantages: 1) the thermal deformation of suspended MEMS structures resulting from a mismatch in the coefficients of thermal expansion of the metal and the oxide in the metal–oxide films is suppressed; and 2) the parasitic capacitance of the sensing electrode routing underneath the proof mass is reduced. Thus, the accelerometer has higher sensitivity and reduced thermal drift. The curvature of the mechanical structures are improved in the temperature span and the noise floor is lowered. In the full temperature span (30 °C–90 °C), change in the radius of curvature per unit change in the temperature was 0.08%/°C for the in-plane accelerometer and 0.37%/°C for the out-of-plane accelerometer. Compared with the typical metal–oxide design, the proposed pure oxide design yielded a >20-fold improvement in radius of curvature change per unit temperature change for the in-plane accelerometer and a fivefold improvement for the out-of-plane accelerometer. Moreover, the noise floor was reduced to 0.40 ( $x$ -axis), 0.21 ( $y$ -axis), and 0.94 mG Hz $^{-1/2}$ ( $z$ -axis), respectively, a 2.2–7.6-fold improvement compared with the metal–oxide design. [2015-0012]

CMOS-MEMS resonators, which are promising building blocks for achieving monolithic integration of MEMS structure, can be used for timing and filtering applications, and control circuitry. SiO2 has been used to make MEMS resonators with quality factor Q > 104, but temperature instability remains a major challenge. In this paper, a design that uses an embedded metal block for temperature compensation is proposed and shows sub-ppm temperature stability (−0.21 ppm/K). A comprehensive analytical model is derived and applied to analyze and optimize the temperature coefficient of frequency (TCF) of the CMOS-MEMS composite material resonator. Comparison with finite element method simulation demonstrates good accuracy. The model can also be applied to predict and analyze the TCF of MEMS resonators with arbitrary mode shape, and its integration with simulation packages enables interactive and efficient design process.

Integrated CMOS-MEMS clamped-clamped beam resonators using metal wet etching technique are demonstrated with passive temperature compensation through the use of SiO2 and large stopband rejection via circuit integration. Such performance is enabled by the high- Q structural material (i.e., SiO2) and embedded electrodes (i.e., metal) for capacitive transduction without the need of complex post-CMOS processes. In virtue of exceptional selectivity of metal wet etchant to SiO2 among CMOS layers, the use of release holes needed for most of isotropic etching processes could be eliminated, hence substantially preserving the integrity of resonator structures. In this paper, CMOS-MEMS clamped-clamped beams with SiO2-rich structural design are fabricated and tested in vacuum under a two-port measurement configuration, exhibiting the lowest temperature coefficient of frequency (TCf) in CMOS-MEMS-based resonators with a turnover point at room temperature. Such a resonator monolithically integrated with readout circuitry using a standard CMOS 0.35 μm 2P4M process is tested with significantly enhanced performance, showing resonator Q's up to 6100, stopband rejection ~60 dB, and low noise floor at center frequency ~8 MHz, therefore benefiting future timing references and RF-MEMS building blocks for next-generation wireless communication applications.

This paper reports the design and implementation of a two-axis capacitive-type accelerometer using well-known two poly-Si processes. The accelerometer design consists of a pendulum proof-mass (bulk Si), a gimbal-spring (poly-Si film), and vertical-comb sensing electrodes. This design has three merits: 1) pendulum proof-mass to produce torque by in-plane acceleration; 2) high-aspect-ratio-micromachined (HARM) gimbal-springs enable the detection of two-axis accelerations; and 3) vertical-combs of different vertical positions enable the differential sensing electrodes design to detect the angular motion. In short, this paper exploits the vertical-comb electrodes for differential capacitive sensing to detect the two-axis in-plane accelerations. Measurement results show that the sensitivities (nonlinearity) of etch direction are 17.87 mV/G (2.65%) of X-axis, and 16.54 mV/G (2.71%) of Y-axis in the excitation range of 0.6~2 G. Due to the HARM gimbal-spring design, the cross axis sensitivity introduced by the Z-axis excitation is less than 0.3% for both X-axis and Y-axis sensing. However, the cross-axis error between the X-axis and the Y-axis sensing elements still need to be improved.

This study presents a novel CMOS-microelectromechanical systems (MEMS) three-axis accelerometer design using Taiwan Semiconductor Manufacturing Company 0.18-μm one-poly-Si six-metal/dielectric CMOS process. The multilayer metal and dielectric stacking features of the CMOS process were exploited to vertically integrate the in-plane and out-of-plane capacitive sensing electrodes. Thus, the three-axis sensing electrodes can be integrated on a single proof mass to reduce the footprint of the accelerometer. Moreover, the fully differential gap-closing sensing electrodes among all three axes are implemented to increase the sensitivities and decrease the noise. The in-plane and out-of-plane sensing gaps are respectively defined by the minimum metal line width and the thickness of one metal layer by means of the metal wet-etching post-CMOS process. Thus, the capacitive sensitivities are further improved. The fully differential gap-closing sensing electrodes also bring the advantage of reduced cross talks between all three axes. As a result, the footprint of the presented three-axis accelerometer structure is only 400 × 400 μm2. Compared with existing commercial or CMOS-MEMS studies, the size is significantly reduced. The measured sensitivities (nonlinearities) are 14.7 mV/G (3.2%) for the X-axis, 15.4 mV/G (1.4%) for the Y-axis, and 14.6 mV/G (2.8%) for the Z-axis.

Integrated CMOS-MEMS free-free beam resonators using pull-in mechanism to enable deep-submicrometer electrode- to-resonator gap spacing without interference in their mechanical boundary conditions (BCs) have been demonstrated simultaneously with low motional impedance and high Q. The key to attaining high Q relies on a decoupling design between pull-in frames for gap reduction and mechanical BCs of resonators. In addition, the use of metal-SiO2 composite structures has been proved to greatly benefit the thermal stability of CMOS-MEMS resonators. Furthermore, tuning electrodes underneath pull-in frames were designed to offer “quasi-linear” frequency tuning capability where linear relationship between tuning voltage and frequency was achieved. In this paper, CMOS-MEMS free-free beam resonators with gap spacings of 110, 210, and 275 nm, respectively, were tested under direct one-port measurement in vacuum, demonstrating a resonator Q greater than 2000 and a motional impedance as low as 112 kΩ and, at the same time, allowing quasi-linear frequency tuning to achieve a total tuning range of 5000 ppm and a sensitivity of 83.3 ppm/V at 11.5 MHz with zero dc power consumption. Such a resonator monolithically integrated with a CMOS amplifier, totally occupying a die area of only 300 μm × 130 μm, was also tested with enhanced performance, benefiting future timing reference and RF synthesizing applications.

This study reports the implementation of a high-performance capacitive-type touch sensor by using the nanoporous anodic aluminum oxide (np-AAO) layer. The np-AAO layer is batch fabricated as the template to enable the direct formation of nanotexture metal film after deposition. The np-AAO is also exploited as the dielectric layer. Thus, the integration of np-AAO layer and the nanotexture metal film is employed to realize a metal-insulator-metal parallel-plate capacitance sensor. The sensitivity of the capacitive-type touch sensor is enhanced by the nanostructures. In application, the Au and Al metal layers and np-AAO are fabricated on Si substrate to form the parallel-plate capacitor. The testing demonstrates the np-AAO-based touch sensor has higher sensitivity. In addition, the detection of small object such as Drosophila using the fabricated np-AAO-based touch sensor is also demonstrated.

This paper reports a capacitive-type CMOSmicroelectromechanical system tactile sensor containing a capacitance-sensing gap filled with polymer. Thus, the equivalent stiffness of the tactile sensor can be modulated by the polymer fill-in, so as to further tune its sensing range. Moreover, the polymer fill-in has a higher dielectric constant to increase the sensitivity of the tactile sensor. In short, the sensing range and sensitivity of the proposed tactile sensor can be easily changed by using the polymer fill-in. In application, the tactile sensor and sensing circuits have been designed and implemented using the 1) TSMC 0.35 μm 2P4M CMOS process and the 2) in-house post-CMOS releasing and polymer-filling processes. The polydimethylsiloxane (PDMS) material with different curing agent ratios has been exploited as the fill-in polymers. The experiment results demonstrate that the equivalent stiffness of tactile sensors can be adjusted from 16.85 to 124.43 kN/m. Thus, the sensitivity of the tactile sensor increases from 1.5 to 42.7 mV/mN by varying the PDMS filling. Moreover, the maximum sensing load is also improved.

This paper presents a novel single proof-mass tri-axis capacitive type complementary metal oxide semiconductor-microelectromechanical system accelerometer to reduce the footprint of the chip. A serpentine out-of-plane (Z-axis) spring is designed to reduce cross-axis sensitivity. The tri-axis accelerometer has been successfully implemented using the TSMC 2P4M process and in-house postprocessing. The die size of this accelerometer chip containing the MEMS structure and sensing circuits is 1.78 × 1.38 mm, a reduction of nearly 50% in chip size. Within the measurement range of ~0.8 6G, the tri-axis accelerometer sensitivities (nonlinearity) of each direction are 0.53 mV/G (2.64%) for the X-axis, 0.28 mV/G (3.15%) for the Y-axis, and 0.2 mV/G (3.36%) for the Z-axis, respectively. In addition, the cross-axis sensitivities of these three axes range from 1% to 8.3% for the same measurement range. The noise floors in each direction are 120 mG/rtHz for the X-axis, 271 mG/rtHz for the Y-axis, and 357 mG/rtHz for the Z-axis.

This paper presents the design and fabrication of a small-form-factor optical pickup head (OPH) for both red and blue wavelength. A holographic optical element (HOE) is used for beam splitting, aberration correction, and servo-signal generation to reduce the number of components and simplify the assembly procedure. In addition to demonstrating this OPH by using existing discrete components, several key components and processes are developed to use micro-electro-mechanical system (MEMS) technology to facilitate batch fabrication and wafer level assembly of the micro OPU.

This paper presents the design, fabrication, and measured properties of a novel zero-insertion-force (ZIF) micro (mu)-connector. The proposed ZIF mu-connector is shown to remedy a number of problems in the existing microelectromechanical-system-based connectors, such as the wearing effect, the poor signal integrity for high-speed signal transmission, and the lack of latch design. The three-mask and silicon-on-insulator wafers are designed for the simultaneous fabrication of terminals and latches. Prototype connectors are demonstrated with five 1800-mum-long, 100-mum-wide, and 2-mum -high terminals on a 150-mum pitch. The terminals and latches are actuated by electrostatic force to avoid the wearing and kinking during the mating process. The terminal is a multimorph cantilever to form a hooklike out-of-plane shape. The controlled shape of the terminal provides a reliable contact at the interface. The properties of the proposed ZIF mu-connector are measured and analyzed, including the out-of-plane shape of the terminal, driving voltage, dc contact resistance, and the RF characteristics. The potential applications of the ZIF mu-connector include the fine-pitch high-speed interconnection, 3-D reworkable packaging, and the performance enhancement of many existing mu-connectors.

This paper presents the design and fabrication of a single-layer out-of-plane thermal actuator. The step-bridge structure design enables bending and then buckling of the actuator in the out-of-plane direction by Joule heating. Moreover, the moving direction of the actuator can be specified by the step structure. In summary, the step-bridge actuator design has the following five merits: (1) The load-deflection relation is easily tuned; (2) the bistable buckling behavior is prevented; (3) the unwanted vibration modes can be suppressed; (4) the delamination problem is prevented; and (5) the bridge structure is stiffer and more stable. The actuator and its application on a lens positioning stage have been implemented using p++ Si layer by bulk micromachining. It demonstrates that a typical actuator would move upward with an amplitude near 13 mum when driven at 54 mW.

This paper reports on novel coilless microscanning mirrors driven by the magnetostatic force that resulted from a magnetic interaction as well as the Lorentz force that is induced by an eddy current. This eliminates complicated coil routing and insulation layer deposition and simplifies fabrication allowing easy integration with micromachining and complementary metal-oxide-semiconductor processes. Bulk micromachined one-axis and two-axis scanning mirrors are demonstrated, displaying 1-D and 2-D scanning patterns. Two-dimensional scanning patterns are easily tuned by varying the combination of driving frequencies. The results show that the diamagnetic (Cu) mirror is mainly driven by the eddy-current-induced Lorentz force, whereas the ferromagnetic (Ni) mirror is mainly driven by the magnetostatic force.

Small-form-factor optical pickups and disk drives have been an area of intense research since the rise of portable consumer electronic products. In current technology, most of the devices are manufactured by the precision assembly of discrete miniaturized optomechanical components. The assembly process can be simplified and cost reduced by using the batch fabrication processes developed in microelectromechanical systems (MEMS). In this paper, the fabrication and testing of optical and actuator components for a MEMS-based optical pickup are presented. A novel design methodology is also applied to the servo control system of the pickup

The technology challenges for miniature optical pickups include high-numerical-aperture objective lens design, servo actuator functions and performance, and component assembly tolerance. In this paper, a microelectromechanical systems (MEMS)-based miniature optical pickup is proposed for DVD and blue disk systems. A high-order diffractive objective lens with a continuous surface relief is designed. Focus, tilt, and tracking servos are implanted with MEMS micro actuators. Preliminary design and test results are presented.

A fully differential CMOS-MEMS double-ended tuning-fork (DETF) oxide resonator fabricated using a 0.18-μm CMOS process has been demonstrated with a Q greater than 4800 and more-than-20-dB stopband rejection at 10.4 MHz. The key to attaining such a performance attributes to the use of oxide structures with embedded metal electrodes, where SiO2 offers a Q enhancement (at least a 3-times-higher Q) as compared to other CMOS-MEMS-based composite resonators with similar structures and vibrating modes and where flexible electrical routing facilitates fully differential configuration to suppress capacitive feedthroughs. In addition, the resonators developed in this work possess a positive temperature coefficient of frequency (TCf) and mode-splitting capability, therefore indicating a great potential for temperature compensation and spurious-mode suppression, respectively. This technology paves a way to realize fully integrated CMOS-MEMS oscillators and filters which might benefit future single-chip transceivers for wireless communications.

The vertical comb-drive actuator (VCA) is a promising component to drive analog as well as scanning micromirrors. This work demonstrates the concept of using ldquosequential engagement of vertical comb electrodesrdquo to improve the linearity and to maximize the deflection for analog micromirror. This concept is achieved by varying the in-plane distribution of comb electrodes. The simulation and experiment results of vertical comb-drive actuator VCA with four different electrode-distribution designs demonstrated the feasibility of this study. In comparison, a modified (curved-profile) VCA was remarkably improved the performance of conventional (straight-profile) VCA. Experiments show that the curved-profile VCA improves the nonlinearity by 34% and increases the maximum angular motion for 2.3-fold.

A novel astigmatism-tunable microlens is reported in this letter. This device is based on a thermal-actuated current-controlled tunable polymer lens. The thermal deformation as well as surface profile of polymer lens is tuned by temperature using the current induced Joule heating. The asymmetric boundary condition is further applied on the silicon conducting ring of the lens to invoke asymmetric deformation of the polymer lens as well as astigmatic change of the polymer lens. To prove the concept, the astigmatism-tunable polydimethylsiloxane lens has been fabricated on the silicon-on-glass wafer. Astigmatism tuning was demonstrated by change of astigmatic focal distance, from 1590 to 44 mum, as input current increased from 0 to 30 mA. In addition, aspect ratios of focal spot shape were varied from -20 to -1.3 and 16 to 1.22 with respect to anterior and posterior focal points. This device provides a feasible solution to the dilemma of astigmatic tuning capability and miniaturization. In summary, the present device has the potential to act as a key component for microelectromechanical systems-based aberration corrector or laser focus-spot shaper.

This paper presents a novel bidirectional-driven microelectromechanical systems (MEMS) light manipulation stage. The designed device consists of two actuators integrated with a lens to act as both tracking (in-plane) and focusing (out-of-plane) components for optical pickup head. The actuator is driven by thermal, as well as magnetic, means. According to a static-load deflection test, this device can achieve bidirection actuation with output displacement up to plusmn54.5 mum. In addition, this MEMS device has a very small form factor and provides an excellent response time and size reduction. It can be employed on the portable optical storage system

In this letter, the concept of driving tunable solid lens using microthermal actuator is presented. This microoptical device is composed of a flexible polydimethylsiloxane (PDMS) lens, silicon conducting ring, and silicon heater. The mismatching of coefficient of thermal expansion and stiffness between PDMS and silicon will lead to the deformation of polymer lens during heating, so as to further change its focal length. To demonstrate the feasibility of this approach, a microfabrication processes have been established to monolithically fabricate the present microoptical device. The typical experiment results show that the tunable focal length was up to 834 mum with an input current of 70 mA

This work presents a novel two-axis gimbaled mirror for optical scanning applications. This scanner has been implemented using the molded surface-micromachining and bulk etching release (MOSBE II) process. Thus, the vertical comb-drive actuators are employed to realize the large stroke. The thin-film electrical routings are employed to drive the actuators individually. The rib-reinforced structures are exploited to increase the stiffness of mirror plate and supporting frame. In addition, the moving space created by backside deep reactive ion etching enables the mirror to perform large out-of-plane angular motion. The measured radius of curvature of reinforced mirror plate is 0.43 m. The maximum scanning angle of two driving axis are plusmn3.8deg at 55 V and plusmn2.4deg at 100 V, respectively. The resonant frequencies associated with the scanning modes are 5.8 and 7.8m kHz, respectively. In addition, the two-dimensional scanning images such as Lissajous patterns are also demonstrated

This study reports the design and implementation of a novel capacitive-type micromachined microphone. The design of the microphone is based on the well-known two poly-Si layers micromachining processes. The microphone consists of a rigid diaphragm (the 2nd poly-Si layer), flexible springs (the 1st ply-Si layer), and rigid back plate (the 1st poly-Si layer). In short, the proposed microphone design has four merits, (1) the rigid diaphragm acting as the acoustic wave receiver and moving electrode is realized using the rib-reinforced poly-Si layer, (2) the flexible spring acting as the electrical routing as well as supporter for diaphragm is implemented using the thin poly-Si film, (3) the electrical routing of rigid diaphragm (moving electrode) is through the central poly-via and the flexible spring, and (4) the rigid plate acting as the stationary electrodes and back plate is fabricated using the high-aspect-ratio (HARM) trench-refilled poly-Si. To demonstrate the feasibility, the two poly-Si microphone has been implemented and tested. Typical measurement results show that the open-circuit sensitivity of the microphone was 12.63 mV/Pa ( -37.97 dBV/Pa) at 1 kHz. (the reference sound-level is 94 dB).

The 24 papers in this special issue are selected from those presented at the 11th IEEE Sensors Conference, held in Taipei, Taiwan during October 28-31, 2012. The selected topics are categorized into i) bio/chemical gas, flow, and humidity sensors; ii) physical, mechanical, and optical sensors and actuators; iii) sensing systems and signal processing; and iv) wireless sensor networks.