A blazed GxL device is described that has high optical efficiency (>70% for RGB lasers), and high contrast ratio (> 10,000:1), and that is highly reliable when used in a large-area laser projection system. The key features were a robust design and precise stress control technology to maintain a uniform shape (bow and tilt) of more than 6,000 ribbons, a 0.25-μm CMOS compatible fabrication processing and planarization techniques to reduce fluctuation of the ribbons, and a reliable Al-Cu reflective film that provided protection against a high-power laser. No degradation in characteristics of the GxL device was observed after operating a 5,000- lumen projector for 2,000 hours and conducting 2,000 temperature cycling tests at -20°C and +80°C. Consequently, the world's largest laser projection screen with a size of 2005 inches (10 m × 50 m) and 6 million pixels (1,080 × 5,760) was demonstrated at the 2005 World Exposition in Aichi, Japan.

Large scale arrays of more than 67k micromirrors of monocrystalline silicon with underlying planar actuation electrodes have been fabricated. The mirrors were fabricated by transferring a 300nm thick silicon layer from a silicon-on-insulator (SOI) wafer to a wafer containing metal electrodes by adhesive wafer bonding in a thermo-compression bonding tool. The bonding was followed by grinding and spin-etching of the handle silicon and the buried oxide, which leaves only the thin device silicon on the electrode wafer. Mirrors and metal plugs were formed using standard micromachining techniques such as sputtering and dry etching. The arrays consist of 16μm×16μm mirrors with 0.7μm wide and 2μm long torsional hinges. Deflection is achieved by applying a voltage between the mirrors and one of two underlying electrodes. It was found that 15V is enough to deflect the mirrors 48nm, which is sufficient to create a black pixel in a diffractive deep UV application that involves modulation of 193nm light. Furthermore, no measurable instability due to plastic hinge deformation or charging could be determined by static deflection for more than one hour. The developed fabrication process is fully CMOS ompatible and can be directly applied to fabricate spatial light modulators (SLM) with mirror arrays in excess of one megapixels with individually addressable analog mirrors that are truly drift free. Application areas are photolithographic mask writers or systems for maskless lithography.

The customers' demand for real life-like display with natural colors and high definition is increasing and hence laser display with the best expression of natural color is being proposed as a way to realize this. In particular, the raster scanning display using the high-speed reflective MEMS scanner plus compact laser sources enables realization of ultrasmall optical engine with great optical efficiency. By the way, in recent years the emerging display systems including FPD (Flat Panel Display) and projection systems based on the microdisplay devices show rapid improvements in terms of picture quality, form factor as well as cost. The object of this paper is introducing a technology analysis of success factors of the MEMS based rater scanning display in order to get high-level development roadmap, through a comparison study with the conventional displays. Proper specifications of brightness, color, contrast, resolution, form factor, power consumption and cost-effectiveness are suggested for mobile projector application. The technical challenges toward achievement of the specifications are summarized.

The Fraunhofer Institute for Photonic Microsystems (IPMS) Dresden (Germany) has developed a one megapixel SLM device with 512 x 2048 individually addressable tilting micromirrors optimized for micro-lithography applications. Besides many other chip parameters SLM surface planarities strongly determine the pattern performance on the lithography masks. This paper presents results on the so called Global Flatness (GF) of the chips which takes into account the complete active area of the large mirror matrix. A description and definition of GF is presented, followed by measurement results on GF prior to chip packaging. Different adhesives are tested for the die bonding process. Bonding on flat test substrates enables the separation of different influences on GF. Impacts of the topography of the die attach and of die bonding process parameters on GF are investigated, optimization potentials such as different dispense modes are tested and discussed. Influences of the chip layout on GF are evaluated. A transfer of Global Flatness measurements to other large area optical chips, e. g. image sensors, is outlined. In the future GF improvements are expected to gain importance due to the ever increasing requirements on CD and CD uniformity performance of mask writers.

In 2001, the sudden downturn of Telecom business changed the optical MEMS landscape. Some MEMS companies who were focusing only on telecom applications shut down (OMM as the most famous example) and many companies stopped their optical MEMS developments (Atmel, Memscap). However, some companies succeed to explore new applications outside the telecom area with their telecom technological platform. Today, there is a renewal of the MOEMS business and there are very interesting market opportunities for DMD. This article describes the new market trends for MOEMS and DMD applications. Several new applications are now appearing aside TV and projections systems that will widespread the use of DMDs. Maskless lithography, wavefront correction (adaptive optics) adaptive front light signal for cars, digital printing are applications currently in development where matrix of micro-mirrors could be used. Maskless lithography is still in a R&D status. It will be a low volume market but high R&D investment application that could benefit to other applications. Market acceptance may be an issue: the two main players ASML and Canon have internal projects under evaluation but it still have to prove that it is an attractive technology. Moreover, other MOEMS markets such are barcode readers, spectrometers, micro bolometers are analyzed and quantified.

MEMS based microdisplays have been given a lot of attention recently since the DLP based products have started to generate substantial revenues for Texas Instrument. Other companies are trying to enter this promising market with similar or alternative concepts. How will he MEMS-based microdisplay market develop until the end of the decade? May other mass markets emerge such as displays for cell phones? Is anyone in the position to challenge TI? This paper presents the results of the analysis of MEMS microdisplay applications and markets in the NEXUS III study.

In recent years, Micro Opto Electro Mechanical Systems (MOEMS) have been reached more and more importance in technical applications. This is caused by the increased reliability of micro systems combined with the reduction of costs by high volume production. In this paper, we will present a resonant scanning grating chip with high diffraction efficiency, developed for the NIR region (900 - 2500 nm), which is based on our resonant micro scanning mirror. The grating was additionally applied to the silicon mirror plate by a chemical wet etch process. Therefore, three different fabrication technologies have been developed, showing high efficiencies in the first diffraction order. Compared to investigations with direct structured gratings in the reflective aluminium surface, gratings with up to 714 lines/mm could be fabricated combined with an improved process parameter control. These new resonant driven scanning gratings are still compatible to the scanning mirror fabrication process. They have a large surface of 3x3 mm² and resonant frequencies of down to 150 Hz, which results in a lower demand on the bandwidth of the electronic read out, when applied to a spectrometer set-up. The maximum mechanically scan angle of the grating mirror plate could be increased to +/- 12° at a driving voltage of 36 V. First measurement results and an improved design of a micro spectrometer, working with only one single InGaAs-Detector in a spectral range of 900 to 2500 nm will be presented and discussed.

Programmable multi-slit masks are required for next generation Multi-Object Spectrograph (MOS) for space as well as for ground-based instruments. A promising solution is the use of MOEMS devices such as micromirror arrays (MMA) or micro-shutter arrays (MSA), which both allow the remote control of the multi-slit configuration in real time. In the present work we developed and microfabricated a novel micro mirror array suited for this application. The requirements are: high contrast, optically flat (λ/20) mirrors in operation, high fill factor, uniform tilt angle over the whole array and low actuation voltage. In order to fulfill these requirements we use a combination of bulk and surface micromachining in silicon. The mirrors are actuated electrostatically by a separate electrode chip. The mirrors are defined by deep reactive ion etching in the 10μm thick device layer of a silicon-on-insulator (SOI) wafer, whereas the suspension of the mirrors is defined by a patterned poly-silicon layer hidden on the backside of the mirrors. The mirror size is 100 x 200 μm² and the dimensions of a typical cantilever suspension are 100 x 5 x 0.6 μm³. On a separate SOI wafer the electrodes and the spacers are processed by using a self aligned delayed mask process. The first results on the mirror chips show that the micromirrors can easily achieve the desired mechanical tilt angle of more than 20° associated with a good surface quality, which is necessary for a high contrast spectroscopy.

Near Infrared (NIR) spectroscopy has developed to an important and useful analysis method over the past years. The existence of compact, portable devices offers a lot of applications possibilities, even in harsh environments. Compact devices, mostly based on detector arrays, are quite costly caused by the expensive Indium Gallium Arsenide (InGaAs) detector arrays. By using MOEMS the set-up can be realised much more efficiently. With an adapted optical set-up detector arrays can be replaced by single element detectors. We have realised a new miniaturised spectrometer based on a scanning micro mirror. The mirror is combined with a diffraction grating and other optical components. It periodically disperses the polychromatic radiation into its spectral components. The radiation is measured by an InGaAs-single element detector, which can be thermoelectrically cooled depending on the application. The radiation coupling is possible either directly or by using fiber optics. It allows an easy attachment of substance samples for reflectance measurements as well as attenuated total reflection (ATR) probes, cuvette holders and flow cells. Lowest noise preamplifiers enable high-precise measurements over a wide dynamic range. With a spectral range of 1000 - 2100 nm and a spectral resolution of approx. 12 nm the device is able to fulfill various requirements. Applications for food stuff industry; clinical chemistry and identification of polymers were tested and will be discussed. Furthermore we will show the advanced optical and mechanical design. In addition advanced performance issues and reliability test results of the device will be reviewed.

The design of a Fabry Perot interferometer/photodiode (FPI/PD) spectral image sensor in the visible wavelength range using CMOS compatible processes is described. Interdigitated PIN PDs with various geometries were fabricated on Si and tested. The spectral response shows that a quantum efficiency of nearly 80% is achieved by the PD in the visible wavelength range. The quantum efficiency increases with increasing gap-width to pitch-width ratio, and the increase is more significant at shorter wavelengths. The optical performance of FPIs with distributed Bragg reflector mirrors and Ag thin film mirrors are modeled and compared. We find that FPIs with Ag mirrors are more suitable for the applications described here. A transmittance of 0.4 can be achieved using 40 nm Ag mirrors. The effects of the mechanical support of the Ag layer and the PD insulating layer on the transmittance of the FPI are investigated theoretically. After adding the supporting layer or insulating layer, the transmittance changes periodically with the thickness of the respective layers. The changing period and amplitude is a function of the refractive index of the respective layer.

Micro- and nano-optical structures offer the possibility to control light on a wavelength scale. This allows further miniaturization of integrated optical circuits. Planar photonic crystal waveguides and microcavities are considered basic building blocks for applications such as microlasers, filters, multiplexers and optical switches. The possibility to tune or switch photonic crystal devices by various ways such as temperature, refractive index change using liquid crystals, free charge carrier density or non linear material effects increases their functionality to form multifunctional, intelligent devices. High-Q cavities in planar photonic crystals exhibit highly localised fields and narrow transmission bands. Due to their strong light confinement even a small perturbation of the localized field can change their transmission properties of the cavity. We present different ways of perturbing the optical environment near a photonic crystal cavity enabling tuning and modulation of the in-plane transmission. Optical switching and wavelength tuning is obtained by means of induced thermo and plasma dispersion effects when focusing a laser onto the cavity structure. The feasibility of high-speed optical integrated circuits based on silicon photonic crystal structures is shown. On the other hand, an AFM tip is used for mechanically tuning and damping the inplane transmission. A future challenge is the integration of more than one silicon tip to combine filter and tuning functionalities and to create a chip-based device.

Diffractive MEMS are interesting for a wide range of applications, including displays, scanners or switching elements. Their advantages are compactness, potentially high actuation speed and in the ability to deflect light at large angles. We have designed and fabricated deformable diffractive MEMS grating to be used as tuning elements for external cavity lasers. The resulting device is compact, has wide tunability and a high operating speed. The initial design is a planar grating where the beams are free-standing and attached to each other using leaf springs. Actuation is achieved through two electrostatic comb drives at either end of the grating. To prevent deformation of the free-standing grating, the device is 10 μm thick made from a Silicon on Insulator (SOI) wafer in a single mask process. At 100V a periodicity tuning of 3% has been measured. The first resonant mode of the grating is measured at 13.8 kHz, allowing high speed actuation. This combination of wide tunability and high operating speed represents state of the art in the domain of tunable MEMS filters. In order to improve diffraction efficiency and to expand the usable wavelength range, a blazed version of the deformable MEMS grating has been designed. A key issue is maintaining the mechanical properties of the original device while providing optically smooth blazed beams. Using a process based on anisotropic KOH etching, blazed gratings have been obtained and preliminary characterization is promising.

A novel MEMS-based modulation scheme is presented as a method to enhance the signal-to-noise ratio (SNR) of silicon photodiodes adapted for the detection of light-emitting bio-reporter signals. Photodiodes are an attractive photodetector choice because they are VLSI compatible, easily miniaturized, highly scalable, and inexpensive. Silicon photodiodes exhibit a wide response range extending from the ultraviolet (UV) to the near infrared (IR) part of the spectrum, which in principle is appropriate for sensing low intensity optical signals. Silicon photodiodes, however, exhibit limited sensitivity to optical dc signals, as the magnitude of the low frequency noise is comparable to signal magnitude. Optical modulation prior to photodetection overcomes the inherent low frequency noise of photodetectors and system detection circuits. The enhancement scheme is based on a design of high frequency optical modulators that operate in the 1-2 kHz range in order to overcome the low frequency spectral noise. We have denominated this MEMS-based scheme Integrated Heterodyne Optical System (IHOS). The modulation efficiency of the proposed architecture can reach up to 50 percent. In order to implement the MOEMS optical modulators, a new two-mask fabrication process was developed that combines high-aspect ratio and low aspect ratio structures at the same device layer (aspect ratio is defined as a ratio between the structure height to its width). Long stroke electrostatic combdrive actuators integrated with folded flexures (high aspect-ratio) were fabricated together to drive large aperture shutters (low aspect ratio). We have denominated this process MASIS (Multiple Aspect Ratio Structural Integration). Under resonant excitation at approximately 1 kHz, MOEMS modulators demonstrated maximum displacement of about 40 microns at an actuation voltage of 15 V peak in air, and 3.5 V peak in vacuum (8 mTorr). Results of analytical solutions and finite element analysis (FEA) simulations are in good agreement with experimental data. A comprehensive model was developed that demonstrates the effective use of IHOS as a SNR enhancer of photodiode sensitivity, providing a 30 dB improvement in the detection limit. This work represents the first attempt for signal enhancement utilizing MEMS technology for detection of low intensity optical signals, and particularly for low intensity optical bio-reporter signals of whole-cell sensors. Whole-cell sensors are genetically modified cells that can be engineered to act as chemical-optical transducers. As the cells are exposed to toxins, photo-emission (bioluminescence) is triggered, providing optical emission levels per cell proportional to the toxicity concentration in the environment. The most important application that we are currently investigating is the implementation of whole-cell sensors as an early detection method against bio-terrorism. Bioluminescence detection becomes a very challenging task, as the maximum photo-emission rate per cell is limited to 300 photons/sec. The main intended application of the IHOS is to utilize it as a seamless add-on that will be placed in between photodiodes and whole-cell sensors, all of which combined into an inexpensive and portable toxicity reader. We believe that the ramifications of this new MEMS-based scheme can be also applicable to a vast number of applications for optical systems in which the SNR needs to be improved.

This paper presents a 9×9 OXC (Optical Cross Connect) utilizing two-dimensional micro-lens scanners, each of which consists of eight 'L' shaped (spider-leg) stage-suspension springs and rotational comb-drive actuators. Silicon was used as a lens material because of the mechanical stability and optical transparency to infrared wavelength of 1.55 μm. The micro lens scanner was fabricated by lens-profile-transferring to the structural layer of an SOI wafer by the RIE (reactive ion etching) from thermally reflowed photoresist. The XY stage moved more than 55 μm independently in the X and Y directions with applied voltage of 65 V. In optical measurement, the coupling loss was 13 dB, and channel uniformity of 9×9 OXC was less than 4.5 dB.

The use of miniaturized optical components for chip level communications is increasing rapidly. The possible applications include: optical switching, signal monitoring, I/O reconfiguration, and add/drop multiplexing. Micro-Opto-Electro-Mechanical Systems (MOEMS) based on customized IC fabrication processes are being used to assemble system-level architecture for integration into mainstream circuitry. MOEMS devices based on dynamic diffractive elements are currently investigated for both their signal routing capabilities and de-multiplexing properties. These characteristics are expected to increase the speed of optical data transfer. This paper focuses on the current status of the MOEMS research program for Free Space Optical inter-chip communication at the College of Nanoscale Science and Engineering, University at Albany- SUNY (CNSE) based on the MEMS Compound Grating (MCG) design. Operational characteristics of these MCG devices have been shown to operate at high voltages (>15V) compared to 5V levels prevalent in conventional integrated circuits. The specific goal of this work is to improve performance while minimizing power consumption. A design change that incorporates a higher capacitance and a lighter suspension system has been studied. A new fabrication process has been constructed utilizing Polyimide as a structural material. Fabrication steps have been optimized for best MCG device performance. Experimental results from both research tasks will be presented.

A miniature Fabry-Perot tunable infrared filter under development at the NASA Goddard Space Flight Center is fabricated using micro opto electromechanical systems (MOEMS) technology. Intended for wide-field imaging spectroscopy in space flight, it features a large 10-mm diameter aperture structure that consists of a set of opposing suspended thin films 500 nanometers in thickness, supported by annular silicon disks. Achieving the desired effective finesse in the MOEMS instrument requires maximizing the RMS flatness in the film. This paper presents surface characterization data for the suspended aperture film prior to, and following application of a multi-layer dielectric mirror. A maximum RMS flatness of 38 nanometers was measured prior to coating, leading to an estimate of the maximum effective finesse of 14. Results show evidence of initial deformation of the silicon support structure due to internal stress in the substrate and thin film layers. Film stress gradients in the dielectric coating on either side of the aperture add convexity and other localized deflections. The design of a tuning system based upon electrostatic positioning with feedback control is presented.

This paper addresses different highly reflective optical coatings on micro scanning mirrors (MSM) for applications in the NIR-VIS-UV- spectral region to enable new applications at high optical power density like laser marking and material treatment. In the common case of MSM with an unprotected Al coating, the absorption limits the maximal power density because of induced heating. In contrast to macroscopic optics HR-micro mirror coatings have to guarantee additional demands like low-stress and CMOS compatibility. Hence, to enable novel high power applications of MSM in the NIR-VIS-UV spectral region highly reflective low-stress coatings have been developed according to a triple strategy: (a) broadband metallic reflectors, (b) dielectric multilayers and (c) enhanced hybrid coatings. For Au and Ag based NIR-coatings an excellent mirror planarity and a reflectance around 99 % (@ 1064 nm) have been achieved, whereas dielectric coatings reached 99.7 % for a (LH)⁴ design and thinner low-stress hybrid NIR-coatings reached up to 99.8 % enabling an improved mirror planarity and excellent laser damage threshold. For the VIS and UV spectral region enhanced hybrid HR-coatings have been favored, because they enable high reflectance of up to 99.7 % @ 633 nm or 98.8 % @ 308 nm in combination with low stress, high mirror planarity and CMOS compatibility.

Electrostatic Micro-actuators are being increasingly used for a wide variety of applications such as spatial light modulators, scanning mirrors, optical cross connects, micro-valves, and others. Usually the electrical forces operate in one direction and are balanced by a mechanical spring. The resulting deflection is then either defined by a mechanical stop, or it is only a meta-stable equilibrium position: at an additional external force or deflection it will snap to a different position, frequently again defined by a mechanical stop. This issue is well known and is often called 'pull-in'. In the often used parallel-plate capacitor actuator, the instability already begins at a deflection of only on third of the original capacitor plate separation. For safety reasons and due to the steep response-curve one can only use an even smaller fraction of the mechanically possible movement. This means, that the gap below the actuator has to be designed very much larger than the required maximum deflection. To get the pre-described force and deflection, a much higher voltage is needed than for potential smaller gap widths. The useable range of deflection for many types of micro-actuators can be extended without the penalty of large drive voltage or low shock resistivity, by employing springs with steeper-than-linear restoring force. Alternatively, the voltage needed for a given range of deflection may be reduced. This paper shows the benefits and how to design and dimension these types of springs.

Since damping is the limiting factor for the reachable maximum deflection, it is a very important issue in the context of resonant microsystems. In this paper, we present an optimized comb design and an extended damping model for out-of-plane scanning micromirrors. It bases on the compact analytical model published by Sandner et al. (at the SPIE conference Photonics Europe in 2004). The basic concept of this model is to attribute viscous damping in the comb gaps as the dominant contributor of damping moments. The model is extended by findings from a fluidmechanical FEM model of an electrode finger. It also considers the effects from pressure and temperature changes. The extended model is verified and discussed in the context of experimental results. The primary goal of damping analysis and optimization is to minimize power consumption and to reduce driving voltage. To consider that, the damping of the out-of-plane electrode comb is discussed in the context of its capacitance. One of the results presented in this paper is a out-of-plane comb-drive with optimized drive efficiency.

We present here a deformable mirror (DM) with a continuous mirror using new zipping actuators, compatible with a simplified collective process and electronic integration. The originality of these new zipping actuators is the presence of a rotation support and a lever to push the mirror. Therefore a small electrostatic gap is enough to obtain large strokes. The device is a bi-directional electrostatic actuator with two other adjacent levers which pull the mirror down. The mirrors are silicon reflective membranes obtained with SOI wafers to bring flexibility in the mechanical design, as well as superior mirror flatness and surface roughness. Using finite element analysis (FEA), simulations is being performed so as to evaluate the performance of the actuators. The recent simulations have shown that the actuator design should enable inter-actuator strokes larger than 1 μm. A first device has been realised to show the feasibility. It is DMs with 19 actuators and a mirror of 1 cm in diameter. Experimentally observed actuator strokes of more than 4.5 μm were obtained for an applied voltage of 60 V when the mirror was pulled down and the first promising results were obtained when the mirror was pushed up from 10 V to 80 V. The specific shape of the links between the membrane and the actuators provides remarkable optical properties. The optical print-through due to the pillar architecture has been reduced to 1.5 nm RMS, which is close to the mirror roughness.

We present a scanning micromirror with 5x better flatness of the mirror plate compared to our previous devices. The devices are designed for a laser scanning displays with VGA resolution. Scanning laser displays are certainly the most demanding application for scanning micromirrors. The fast axis must provide a large mirror plate that remains flat, when deflected to large angles at high frequency. The presented devices meet the specifications for VGA-resolution (640x480 pixels). Oscillation frequency is 16kHz. The mirror-plate has 1mm diameter and can be deflected by +/-10°. Dynamic deformation is below lamba/10 under these conditions. The devices are fabricated in the established SOI process of Fraunhofer IPMS Dresden. Mirror plate and springs are made of 30um of crystalline silicon. Operation is resonant with lateral out-of-plane comb-drives. In this article we present the design, simulation results and measurement results.

In previous work, we proposed a method for imaging using micro optical electromechanical (MOEM) mirrors. Our solution was to introduce into the imaging sensor optics a 2-D micro-mirror array. This device provides high resolution images with a wide field of view. In this paper, we provide further simulations that validate the functionality of our system design. In addition, we present our first system prototype that can produce an image with higher resolution and support a wider field of view than the image sensor employed in the system.

The concentric circles type and saw-tooth type of micro grating device based upon the diffraction theory are proposed in this study. The geometry dimension of micro optical device is 200 × 200 μm², the interval of grating is 4 μm, and the depth is 0.75 μm. The Micro Array Thermal Actuator, MATA, is applied to drive the micro grating device, and the pre-elevating structure is designed to lift the micro grating device by the residual stress of polysilicon combined with metal. The micro grating device is fabricated by Surface Micromachining for applications and research technology platform, SMart, common process. The incident ray of He-Ne laser focused by a lens which focal length is 250 mm is applied to be the light source for the experiment, and then analyzes the optical information of the outgoing ray. From the experimental results, the basic optical features are examined based upon the concentric circles type and saw-tooth type of micro grating device, respectively. The outgoing ray angle of central spot is 60° in theory. The measurements are 59.475° for the concentric circles type and 59.88° for the saw-tooth type. The outgoing ray angle of the first stripe is 46.9° in theory, and 46.81° for the concentric circles type and 46.67° for the saw-tooth type are measured from the experiment. The variation of outgoing ray angle is smaller than 1% compared the measurement results with theory of diffraction on the central spot and first stripe characteristics. The work successfully demonstrates the micro grating device with highly accurate performance by the verification of optical information. All of the efforts will be contributed to Controlled Blazed Diffraction micro grating device, CBDMG, and that will be the main device of Integrate Opto-Electronics applied on display to develop in the future.

A novel laterally driven mechanism is proposed and studied to solve the pull-in problem of electrostatic actuation in MEMS for use in simple Fabry-Perot interferometers (FPI) with a large tuning range. This method is to build electrodes that are not directly opposite to each other, but rather are laterally shifted. Mathematica calculations show that laterally driven beams require a smaller operating voltage than do some other methods, and cover nearly the full travel range. It is also found that driving performance is influenced by the structure's lateral gap. Too small a lateral gap still yields pull-in failure. For excessively large lateral gap, the pull-in function is not effective. Smaller lateral gaps have lower operating voltage, but larger lateral gaps have better operating stability. A test structure consisting of 40 aluminum beams suspended across two poles has been designed and fabricated. Directly below each test beam is located a capacitive test electrode. Next to each test electrode are two lateral driving electrodes. A driving voltage is applied across the aluminum test beams and lateral electrodes, pulling down the beam and causing the capacitance to change between the test beam and test electrode. By measuring this change, the lateral drive method is verified and characterized.