Search

Microsystems sensors are implemented on a fiber optics based platform towards use in magnetic resonance imaging assisted interventions. The presented platform offers real-time and in-situ pressure, temperature, and localization feedback during imaging assisted surgical procedures. This multi-sensor platform fits into an interventional medical device with a diameter of 2.5 mm. A polymer cap with perforation is utilized for circulation of blood in the vessel to allow correct monitoring of the temperature and pressure in real time. Graded Index (GRIN) lenses were utilized at the tip of the fiber cables improved optical signal collection efficiency. Three light sources having different wavelengths were utilized each for one sensor; a 637 nm laser, a 780 nm laser, and a 875 nm LED (50 nm bandwidth) for pressure, localization, and temperature sensors, respectively. Pressure sensing is performed by a released polymer-metal hybrid membrane having a diffraction grating interferometer readout scheme. Temperature sensing is accomplished based on the change of absorption and transmission in semiconductors (i.e. GaAs) due to variations of energy bandgap with temperature. Localization of the medical device is acquired based on magneto-optical Kerr effect where Iron Oxide magnetic material is employed. The sensor chip revealed a temperature precision of $\pm 0.22\;^{\circ }$ C, a pressure resolution of 1 mmHg and a localization resolution of 3 mm, where all values are relevant to medical practice. Integration of the sensors developed in this study helps medical devices such as catheters and stents, allow a new horizon in interventional surgery.

Although molecular communication systems have been shown to bear great potential for many useful in-body applications, they require the intervention, action, or input of an out-of-body actor. From an Internet of Bio-Nano Things perspective, a successful overall network aims to bring together the two links belonging to the in-body and out-of-body networks for end-to-end communications. For most applications, the uplink from the in-body sensor is more significant since it provides the multi-scalar connection required to relay the information sensed and carried by the molecular communication system to a macro-scale smart terminal. This article proposes two different mechanisms to sense the output of the molecular communication system and transmit the information to an on-body reader. Each mechanism involves different genetically engineered bacteria and specific antenna designs. An experimental setup is provided to demonstrate each proposed concept. The results constitute a proof of concept to detect the in-body bacterial activity from the on-body reader.

Recent advances in solid-state technologies have enabled the development of light-emitting diodes (LEDs) with favorable features such as long life expectancy, low-power consumption, and reduced heat dissipation. Visible-light communication (VLC) is a short-range wireless access technology that deploys LEDs as wireless transmitters in addition to their primary task of illumination. The major limitation for the design of high-speed VLC systems is the electrical (modulation) bandwidth of the LED. In this study, we investigate the electrical characteristics of a number of off-the-shelf LEDs. Specifically, we determine their frequency responses and match them to their small-signal models. The electrical bandwidths of measured LEDs vary from 250 kHz to 20 MHz and depend on the emitted color and internal circuitry. As a verification of our measurements, we use the sample LEDs as a transmitter in a VLC system setup and determine the supported data rates. The equivalent circuit model is utilized to compare with the measured modulation characteristic of the LED. Furthermore, the bias current effect on the modulation bandwidth is presented. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)

This paper describes a microwave resonator incorporating microfluidic lab-on-chip sensor system capable of performing simultaneous differential measurement based sensing of liquid samples. The resonators are split-ring resonator shapes made of gold on glass substrates. Directly bonded on glass substrates are polydimethylsiloxane microchannels. Sensor system design incorporates a pair of identical resonators, one of which performs reference reading from the background. Tracking the difference of the responses of both resonators simultaneously, rather than a single one, is used to obtain a more linear and noise-free reading. The sensor system was produced with conventional fabrication techniques. It is compatible with low-cost, simple, easy to handle sensing applications. Results indicate that reliable differential measurement was possible owing to a well-matched pair of sensors with a response error as low as 0.1%. It was also demonstrated that differential measurement capability enables sensing with improved linearity. Measurements were performed with glucose solutions in the range of 3.2–16.1 mM, achieving a sensitivity of 0.16 MHz/mM.

We present a biosensor based on electromagnetic ring resonator for label-free detection of glucose. The sensing mechanism is based on the principle that the resonant frequencies of such structures depend on the structure geometry and the physical properties of the medium they are in, such as electrical permittivity. The sensor in this paper uses a split-ring resonator fabricated on a flame retardant four substrate via simple printed circuit board fabrication techniques. Glucose oxidase enzyme was incorporated in order to provide biospecificity for glucose. Conductive polymer poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) , also known as PEDOT:PSS, was used for the immobilization of the enzyme on sensor surface. The redshift of the resonant frequency of the sensor in response to DI water, glucose, and NaCl solutions are shown to be in agreement with simulation results and theoretical expectations. In the presence of the enzyme, the sensor loaded with a glucose solution was observed to experience a resonant frequency shift of 17.5 MHz in 15 min, whereas other reagents such as fructose, sucrose, and NaCl did not respond significantly, confirming the biospecificity. The sensor was measured to have a sensitivity of 0.107 MHz/mgml $^{-1}$ .

High throughput microfluidic devices coupled with optical detection systems bring several advantages to study molecular communication (MC) by mimicking capillary vessels and arterioles. Motivated by this, we present an MC platform using fluorescence polystyrene (PS) beads as messenger molecules to transfer encoded information in microfluidic channels via flow induced diffusion. To this end, we couple multiple production and analysis techniques to construct and characterize our micro scale MC system. PS microbeads are introduced into microchannels via programmable syringe pumps serving as transmitters, while the received signal is recorded by inverted fluorescence microscope. Time lapsed images of microparticles are presented as they move across diffusion channels.

Microfluidics is an innovative technological platform with a vast potential to streamline processes in biology, chemistry, and biomedical fields. Microfluidic integrated biosensors attract much attention due to extreme miniaturization, low sample consumption, and increased homogeneity in mixing conditions, leading to enhanced sensitivity. Nowadays, many researchers focus on inexpensive and flexible laser production of polymer-based microfluidic devices for sensing applications due to their ease of production and rapid processing benefits. In this article, we present some key factors for the simple and rapid production of microfluidic components of the microwave sensor by using the CO2 laser ablation technique. The technique does not require any cleanroom or complex laboratory setups and provides short fabrication times for prototyping. It is observed that, at high laser power (30 W) and low scan speed (125 cm s(-1)), both the channel depth and the surface roughness increase greatly as opposed to channel waviness. It is also demonstrated that heat treatment is a viable method to reduce the channel roughness with a trade of channel depth. In the second section, prepared channels are bonded onto the split ring resonators (SRRs) fabricated using polymethyl methacrylate as a substrate. Power reflection measurements from SRR are performed using a continuous flow system that injects 100 mM glucose solutions into the channels. Change of dielectric constant due to glucose loading generates a meaningful resonance frequency shift, showing a possible use scenario of the device as a biosensor.

A MEMS based novel THz detector structure is designed and realized by micro fabrication. The detector is then characterized to extract its mechanical performance. Operating in 0.5–2 THz band, the detector has a pixel size of 200 μm × 200 μm. Bimaterial suspension legs consist of Parylene-C and titanium, the pair of which provides a high mismatch in coefficients of thermal expansion. The pixel is a suspended Parylene-C structure having a 200 nm-thick titanium metallization. Operation principle relies on conversion of absorbed THz radiation into heat energy on the pixel. This increases the temperature of the free-standing microstructure that is thermally isolated from the substrate. The increase in temperature induces mechanical deflection due to bimaterial springs. The detector is designed to deliver a detectivity (D*) of 2 × 109 cm Hz−1/2/W and a refresh rate of 20 Hz.

A micro-scanner made of stainless-steel is fabricated via laser cutting technology for 3D Lissajous confocal imaging. The multi-gimbaled structure of the device provides two orthogonal torsional modes and three different out-of-plane modes. Torsional modes can be used to achieve 2D scan and all of the out-of-plane modes can be used in changing the focus of the micro-scanner to achieve a 3D scanning pattern. One of the out-of-plane modes along with two orthogonal torsional modes can be employed for scanning a large depth-stack in sparse fashion while another out-of-plane mode can satisfy a much higher scan fill-rate with less field of view (FOV). Simulations of the micro-scanner are obtained using finite element method (FEM) software and compared with the characterization data gathered from Laser Doppler Vibrometer (LDV). Using various out-of-plane modes, the constructed fill patterns are simulated on MATLAB and fill rates compared.

Next-generation electronic and optical devices demand high-resolution patterning techniques and high-throughput fabrication. Thereby Field-Emission Scanning Probe Lithography (FE-SPL) is a direct writing method that provides high resolution, excellent overlay alignment accuracy and high fidelity nanopatterns. As a demonstration of the patterning technology, single-electron transistors as well as split ring electromagnetic resonators are fabricated through a combination of FE-SPL and plasma etching at cryogenic temperatures.

Sub-10 nanometer lithography is opening a new area for beyond-CMOS devices. Regarding to single nano-digit manufacturing we have established a new maskless patterning scheme by using field-emission, current controlled Scanning Probe Lithography (cc-SPL) in order to create optical nanodevices in thin silicon-oninsulator (SOI) substrates. This work aims to manufacture split ring resonators into calixarene resist by using SPL, while plasma etching at cryogenic temperatures is applied for an efficient pattern transfer into the underlying Si layer. Such electromagnetic resonators take the form of a ring with a narrow gap, whose 2D array was the first left-handed material tailored to demonstrate the so-called left-hand behavior of the wave propagation. It is shown that the resonance frequency can be tuned with the feature size of the resonator, and the resonance frequency can be shifted further into near infrared or even visible light regions., Istanbul Development Agency (ISTKA)

A MEMS based novel THz detector structure is designed and realized by micro fabrication. The detector is then characterized to extract its mechanical performance. Operating in 1-5 THz band, the detector has a pixel size of 200μm × 200μm. Bimaterial suspension legs consist of Parylene-C and titanium, the pair of which provides a high mismatch in coefficients of thermal expansion. The pixel is a suspended Parylene-C structure having a 200 nm-thick titanium metallization. Operation principle relies on conversion of absorbed THz radiation into heat energy on the pixel. This increases the temperature of the free-standing microstructure that is thermally isolated from the substrate. The increase in temperature induces mechanical deflection due to bimaterial springs. The detector is designed to deliver a noise equivalent temperature difference (NETD) less than 500 mK and a refresh rate of 30Hz.

A suspended array of square metallic patches on a thin dielectric layer is introduced as a terahertz absorber. The absorber is fabricated on a metalized substrate and the device exhibits metamaterial behavior at specific frequencies determined by the size of the patches. It is feasible to place patches with different sizes in an array formation for a broadband absorber. Design of the absorber is described using electromagnetic simulations. The absorber structure was fabricated on a silicon wafer and its characteristics were measured using a terahertz time domain spectroscope. The measured data match well the simulations indicating strong absorption peaks in a band of 0.5-2 THz.

This paper presents a biosensor based on laser-machined metallic split-ring resonators embedded in hydrophilic polymer matrices for glaucoma monitoring. The inner and outer radii of the annular resonators are optimized using a finite-element model for the anterior part of the fibrous layer of human eye. The split-ring resonators are designed to have resonant frequencies in S-band. The devices are fabricated by laser cutting of 15 μm-thick aluminum sheets. Split-ring resonators are then embedded into photo-polymerized cross-linked hydrogels, which are used to prepare hydrophilic polymer matrices. The change in the resonance characteristics of the device is obtained with respect to the change in the curvature. The sensitivity of the sensor is calculated as −24.12 MHz/mm per unit change in the radius of the curvature.

Use of microwave resonator-based sensors is a relatively new approach for the detection of biological reagents. Sensing mechanism is based on the tracking of the resonant frequency on electromagnetic resonator. Resonant frequency depends on structure geometry and material but is also affected by secondary changes in environment. Addition of a reference resonator to suppress these effects is proposed in this work. Identical sensor structures designed at 2 GHz, fabricated using low-cost processes are used in experiments to demonstrate the use of a resonator pair for sensing of glucose in solutions, yielding a sensitivity of 34.72 MHz/ (mg/mL).

A stainless-steel based micro-scanner with magnetic actuation is fabricated via laser-cutting technology targeted for confocal microscopy. Laser cutting offers low-cost and high speed fabrication of such scanners. The device is designed to establish a 2D Lissajous pattern. For a coil drive of 180 mA, fabricated scanner is able to deliver 4 degrees of optical scan angle for both slow scan and fast scan axes at 663 Hz and 2211 Hz, respectively. Fabricated mirror is integrated into a confocal microscopy setup and tested with the United States Air Force target accomplishing a 200 μm × 200 μm field of view and sub 10 μm resolution. With further improvement, our scanner will contribute to manufacturing of low-cost and compact scanning microscopy technologies.

In this work, applicability to the optical communication systems of photodiodes realized with standard CMOS fabrication processes, which can be integrated to microelectronic systems at low costs. A photodiode fabricated with UMC 180 nm standard CMOS process on a silicon substrate within a 1.05 mm χ 1.00 mm area is experimented with as an optical receiver in a setup where LEDs of different visible wavelengths are used as sources. Performance of the CMOS photodiode was compared to that of a Thorlabs PDA10A-EC photodiode used as a reference. In the experiments, it was observed that the communication bandwidth of the reference photodiode is in the 0.87–1.68 MHz range and that the CMOS photodiode can achieve comparable bandwidths in the range of 0.70–1.37 MHz. A square wave of 200 kHz frequency can be carried via an optical communication system using the CMOS photodiode without suffering from significant distortions.

An optoelectrical power supply unit compatible with standard CMOS processes designed for microscale applications is presented. The system is based on an earlier version consisting of a photodiode that converts optical power to electrical power, and a dc/dc converter that increases the photodiode anode voltage to desirable levels. It has the ability to operate continuously or intermittently. The latter operation mode employs additional system elements and requires the modulation of the input laser beam. A prototype was fabricated in UMC 0.18-mu m triple-well standard CMOS process along with a direct conversion self-mixing receiver block on a die of 1525 mu m x 1525 mu m area. Performance measurements were done using a laser source of 650-nm wavelength at different power levels. For an input laser power of 80 mW, the source can provide an output current of 2.18 mA at a supply voltage of 1.2 V. The proposed system can be used to power integrated digital and low-power analog communication and medical microsystems.

This paper summarizes the design, fabrication, and characterization of a magnetically actuated stainless-steel based micro-scanner. The out-of-plane deflection of the proposed device is calculated by using a custom depth scan setup. The main advantage of laser cutting technology, which is utilized in manufacturing the proposed steel scanner, is its rapid fabrication capability at low cost, while still offering high frequency scan for imaging and/or ablation with high frame-rates. In the lateral plane, the scanner delivers 5 degrees of total optical scan angle for a current drive of 60 mA for both slow scan and fast scan axes at 998 Hz and 2795 Hz, respectively. Furthermore, the device provides an out-of-plane pumping mode at 1723 Hz that could be utilized for axial scanning to create focal shift at the target. Fabricated scanner is integrated into a confocal microscopy setup and tested with a resolution target and a Convallaria rhizome sample, accomplishing a 240 m 240 m field of view with 2.8 m resolution. The device offers 218 m depth of field (in tissue) and based on acquired resonance frequencies, we estimate rapid scanning of a three-dimensional block of tissue (240 m 240 m 218 m size) with approximately 3 block per second with 50% fill rate and total coverage of 87% for 1 s scan. Finally, a custom setup is proposed for 3D imaging and validity of the 3D beam steering of the micro-scanner is tested.

Glaucoma is an eye disease that may cause blindness by damaging the optic nerve due to elevation of the intraocular pressure. Patients with glaucoma require monitoring of intraocular pressure. This paper presents split-ring resonator-based strain sensors designed and characterized for glaucoma detection application. The geometry of the sensor is optimized such that it can be embedded in a conventional contact lens. Silver conductive paint is used to form the sensors realized on flexible substrates made of cellulose acetate and latex rubber. The devices are excited and interrogated using a pair of monopole antennas. Scattering parameters are measured between the ports of the antennas, and the characteristics of devices with different curvature profiles are obtained. Finite-element based models are developed to analyse the operation of the devices and to optimize the sensor structure. The sensitivity of the device, i.e. the change in resonant frequency for a unit change in radius of curvature, on acetate film is experimentally characterized as -4.73 MHz/mm and the sensitivity of the device on latex is 33.2 MHz/mm. The experimental results supported by finite-element based models indicate that the demonstrated device is suitable for glaucoma diagnosis and monitoring. (C) 2017 Elsevier B.V. All rights reserved.

This paper presents a low-power optically powered receiver system designed in 0.18 mu m triple well UMC complementary metal-oxide-semiconductor (CMOS) technology. Optical transmission is used for both power delivery and signal transmission. The power of the whole system can be supplied in two different configurations, namely continuous and intermittent mode configurations. In the continuous mode configuration, the optical power of a 650-nm laser source is received and delivered to the electronic circuits by a set of on-chip CMOS photodiodes. In the intermittent mode configuration, a low voltage DC-DC converter is used to boost a single on-chip CMOS photodiode voltage of 0.65 V up to 1.8 V. Additionally, in this configuration, optical switching is used for charging and discharging of a storage capacitor to obtain currents in milliampere range for the proper operation. The front-end part of the receiver consists of a fully differential low noise amplifier (LNA), a fully differential gain stage, a single output double balanced Gilbert-cell mixer, and a laser driver. The front-end part can operate properly by one on-chip photodiode voltage of 0.65 V. System performance is demonstrated for a sample 1.5 T magnetic resonance imaging (MRI) application. Experiments show that LNA of the receiver has a low input referred noise voltage density of 4 nV/root Hz at the supply voltage of 0.65 V. The receiver transmits the signal via a fiber-coupled infrared (IR) laser diode (lambda = 1310 nm). The results show that the system can continuously process a minimum detectable signal (MDS) of dBm at an incident optical power of 20 mW while the total power consumption of the receiver and the IR diode is 700 mu W. In the intermittent mode configuration, the system gain is measured to be 6 dB greater, and the average power consumption is measured as 214 mu W When the incident laser is modulated with a rectangular pulse wave of 40 ms period with 95% duty cycle.

A novel two-dimensional display that exploits the large deflection of composite-polymer (FR4) based mechanical actuator and high optical performance of inorganic LEDs is implemented. Structure of the display consists of a 1D semiconductor LED array integrated on a electromagnetically actuated platform. Refresh rate of the display is controlled by the resonant movement of the mechanical device, whereas the fast-scan is performed by the synchronous electronic modulation of the inorganic LED devices. Since composite polymer structural material is used as the mechanical structure, a proper refresh rate of 100 Hz is implemented by engineering the spring dimensions. Simultaneous motion of the slow-scan resonant movement along with the modulation of 1D LED array in perpendicular direction to the slow-scan axis enables the generation virtual pixels on a 20 image plane. Refresh rate is implemented at 99 Hz, giving a peak displacement of 2.45 mm at a drive power of 85 mW. Resolution of the display is 20 x 40 pixel on a physical size of 8 min x 2.25 mm. When considering only the LED array, the proposed display consumes 14% more power compared to a conventional dot-matrix LED display of the same performance. The advantages of using a significantly less amount of LED devices results in a more reliable operation, in terms of low probability of dead-pixel failure, easily controllable LED-to-LED variations. Robustness of the display is proven by insignificant variations of the performance (quality factor, resonance frequency and peak displacement) parameters for 3 million cycles. (C) 2011 Elsevier B.V. All rights reserved.

Resonance frequency tuning in magnetic micromechanical resonators remains a primary field of study for frequency reference applications. The use of magnetic micromechanical resonators for innovative timing, oscillator and sensing applications necessitates a platform for the precise control of the resonance frequency. The present work addresses a deformation-based technique for tuning the resonance frequency of nickel micromechanical resonators. Frequency response is measured through magnetic actuation and optical readout. The tuning approach is based on a combination of flexural deformation and uniaxial strain. The bending deformation is achieved by using a DC current through the microbeam. This magnetomotive mechanism reduces the resonance frequency by about 13% for a maximum DC current of 80 mA. A substrate bending method is used for applying uniaxial strain to increase the resonance frequency by about 8%. A bi-directional frequency modulation is thus demonstrated by utilizing both deformation techniques. The interpretation of results is carried out by finite element analysis and electromechanical analogy in an equivalent circuit. Using deformation techniques, this study provides a rigorous approach to control the resonance frequency of magnetic micromechanical resonators.

In this paper, a novel all-polymer integrated microsystem, which realizes a 2-D display by integrating a 1-D array of polymer light-emitting diodes (PLEDs) with a polymer scanner of microelectromechanical system (MEMS), is presented. Electronic modulation of PLEDs forms the first dimension of the display (fast scan), and the scanner actuation orthogonal to the direction of PLED lineup forms the second one (slow scan). MEMS scanner (actuator) is fabricated on a polymer composite (FR4 material) with a double-sided process using lithography to pattern copper lines and laser micromachining to cut the scanner outline. PLEDs are fabricated on polyethylene terephthalate sheets. They have a thin-film structure of indium tin oxide, poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate), poly [2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene], and aluminum. The scanner is actuated electromagnetically in its slow-scan resonance mode at 49 Hz, generating a maximum displacement of 3.5 mm at a drive power of 84 mW with the help of a mini permanent magnet attached to the tip of the scanner and an off-chip energizing coil. Turn-on voltage of a PLED is 7.5 V, and each one generate a luminance of 0.3 cd/m2 at 13 V, consuming 1.1-mA current. Successful operation of the integrated-display system is shown by forming a checker box image with a resolution of 20 × 7 and a size of 9 mm by 3.4 mm.

A microwave ring resonator based glucose detecting biosensor incorporating glucose oxidase enzyme is presented. Sensor uses a split ring resonator as a transducer, where the sensing operation is done by the observation of shifts in its resonant frequency. Resonator was fabricated with basic fabrication techniques and the enzyme was immobilized via conductive polymer agent PEDOT:PSS. Experimentally observed redshift of resonant frequency of the sensor in response to different loading conditions are in agreement with simulation results and theoretical expectations. Sensor selectivity is confirmed with control experiments conducted with NaCl solutions. Experiments done with different glucose solution concentrations yielded a sensor sensitivity of 0.174MHz/mgml-1.

This paper presents split-ring resonator-based strain sensors designed and characterized for glaucoma detection application. The geometry of the sensor is optimized such that it can be embedded in a contact lens. Silver conductive paint is to form the sensors realized on flexible substrates made of cellulose acetate and latex rubber. The devices are excited and interrogated using a pair of monopole antennas and the characteristics of devices with different curvature profiles are obtained. The sensitivity of the device, i.e. the change in resonant frequency for a unit change in radius of curvature, on acetate film is calculated as -4.73 MHz/mm and the sensitivity of the device on latex is 33.2 MHz/mm. The results indicate that the demonstrated device is suitable for glaucoma diagnosis.

Resonant mode polymer-based electromagnetic scanners are developed for barcode reading applications. The electromagnetic scanner consists of a mirror suspended by a polymer cantilever beam, a permalloy sheet attached to the mirror, and an external coil to generate the driving magnetic field. The simple fabrication process involves polymer molding and electroplating of magnetic material, yielding inexpensive devices suitable for high volume manufacturing. Mechanical and magnetic modeling of the device as well as analytical, numerical and experimental results are presented. A barcode reading system is demonstrated successfully using this inexpensive, easy to manufacture scanner. Fabricated cantilever scanners achieve an optical θ·D product of 123 ◦ mm at 56.5 Hz, consuming an actuation power of 168 mW. 2D actuation of the cantilever scanners is also demonstrated.

A novel microelectromechanical systems (MEMS) actuation technique is developed for retinal scanning display and imaging applications allowing effective drive of a two-axes scanning mirror to wide angles at high frequency. Modeling of the device in mechanical and electrical domains, as well as the experimental characterization is described. Full optical scan angles of 65deg and 53deg are achieved for slow (60 Hz sawtooth) and fast (21.3 kHz sinusoid) scan directions, respectively. In combination with a mirror size of 1.5 mm, a resulting thetasopt D product of 79.5 degmiddotmm for fast axis is obtained. This two-dimensional (2-D) magnetic actuation technique delivers sufficient torque to allow non-resonant operation as low as dc in the slow-scan axis while at the same time allowing one-atmosphere operation even at fast-scan axis frequencies large enough to support SXGA (1280 times 1024) resolution scanned beam displays

The reason behind the majority of difficulties encountered in the integration of nanoscale objects with microelectromechanical systems can almost always be traced back to the lack of batch-compatible fabrication techniques at the nanoscale. On the one hand, self-assembly products do not allow a high level of control on their orientation and numbers, and hence, their attachment to a micro device is problematic. On the other hand, top-down approaches, such as e-beam lithography, are far from satisfying the needs of mass fabrication due to their expensive and serial working principle. To overcome the difficulties in micro–nano integration, a batch-compatible nanowire fabrication technique is presented, which is based on fabricating nanowires using simple lithographic techniques and relying on guided self-assembly. The technique is based on creating cracks with a predetermined number and orientation in a thin SiO2 coating on Si substrate, and then filling the cracks with an appropriate material of choice. After the SiO2 coating is removed, nanowires remain on the Si surface as a replica of the crack network. The technique, previously confined to electroless deposition, is now extended to include electroplating, enabling the fabrication of nanowires of various alloys. As an example, arrays of NiFe nanowires are introduced and their magnetic behaviour is verified.

A deep reactive ion etch (DRIE) process for fabrication of high aspect ratio trenches has been developed. Trenches with aspect ratios exceeding 20 and vertical sidewalls with low roughness have been demonstrated. The process has successfully been used in the fabrication of silicononinsulator (SOI) released comb drive based resonators and tunable capacitors for MEMS applications. Brief characterizations of the devices are presented.

This paper presents experimental results on MEMS metallic addon postfabrication effects on complementary metal oxide semiconductor (CMOS) transistors. Two versions of add-on processing, that use either e-beam evaporation or magnetron sputtering, are compared through investigation of the electrical parameters of n-channel and p-channel transistors. The magnetron sputtering technique is shown to be compatible with standard CMOS electronics without any restriction of the metal types and annealing requirements.

A magnetically actuated microscanner is used in a laser scanning microscopy application. Stress distribution along the circular-profiled flexure is compared with a rectangular counterpart in finite-element environment. Magnetic actuation mechanism of the scanning unit is explained in detail. Moreover, reliability of the scanner is tested for 3×106 cycle. The scanning device is designed to meet a confocal microscopy application providing 100 μm×100 μm field of view and

In this work, a fully optical Complementary Metal Oxide Semiconductor (CMOS) based catheter tracking system designed for 3 T Magnetic Resonance Imaging (MRI) environment is presented. The system aims to solve the Radio Frequency (RF) induced heating problem present in conventional wired catheter tracking systems used in MRI. It is based on an integrated circuit, consisting of a receiver and an optical power supply unit. The optical power supply unit includes a single on-chip photodiode and a DC-DC converter that boosts the low photodiode voltage output to voltages greater than 1.5 V. Through an optically driven switch, the accumulated charge on an a storage capacitor is transferred to the rest of the system. This operation is novel in the way that it is fully optical and the switch control is done through modulation of the applied light. An on-chip local oscillator signal for the receiver is avoided by application of an RF signal that is generated by the MRI machine at the receiving period. The signals received by a micro-coil antenna are processed by the on-chip direct conversion receiver. The processed signal is then transferred, also optically, to the outside world for tracking purposes. The frequency encoding method is used for MRI tracking. Operation with various levels of external optical power does not generate noticeble temperature increase in the system. The overall system is successfully tested in a 3 T MRI machine to demonstrate its full operation.

We present a polymer-based mechanical sensor with an integrated strain sensor element. Conventionally, silicon has been used as a piezoresistive material due to its high gauge factor and thereby high sensitivity to strain changes in the sensor. By using the fact that the polymer SU-8 [1] is much softer than silicon and that a gold resistor is easily incorporated in SU-8, we have proven that a SU-8-based cantilever sensor is almost as sensitive to stress changes as the silicon piezoresistive cantilever. First, the surface stress sensing principle is discussed, from which it can be shown that the SU-8-based sensor is nearly as sensitive as the silicon based mechanical sensor. We hereafter demonstrate the chip fabrication technology of such a sensor, which includes multiple SU-8 and gold layer deposition. The SU-8-based mechanical sensor is finally characterized with respect to sensitivity, noise and device failure. The characterization shows that there is a good agreement between the expected and the obtained performance.

A split-ring resonator-based microwave sensor comprises a metallic ring with a slit and integrated monopole patch antennas on top of a dielectric substrate. The resonant frequency of the device is measured as 2.12 GHz. The device is demonstrated as a resonant biomolecular sensor where the interactions between heparin and fibroblast growth factor 2 are probed. The sensitivity of the device is obtained as 3.7 kHz/(ng/ml) with respect to changes in concentration of heparin.