Multilevel beam SOI-MEMS fabrication and applications

Milanović, V.

doi:10.1109/icecs.2002.1045389

Cited by 22 publications

(17 citation statements)

References 9 publications

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“…However, it has several disadvantages for optical applications, such as surface curvature induced by residual stress, absorption of visible light, and poor performance as an optical detector. To increase the stiffness and reduce the effect of residual stress, structures employing high-aspect-ratio poly-silicon processes or silicon-on-insulation (SOI) wafers were proposed [14]- [16]. However, the high deposition temperature of poly-silicon in these processes may affect the performance of photo detectors or circuits if they are to be fabricated on the same substrate.…”

Section: Electrooptical Chipmentioning

confidence: 99%

Design, Fabrication, and Control of Components in MEMS-Based Optical Pickups

et al. 2007

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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.Index Terms-Actuator, microelectromechanical systems (MEMS), optical pickup, silicon on insulation (SOI), small form factor.

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Section: Electrooptical Chipmentioning

confidence: 99%

Design, Fabrication, and Control of Components in MEMS-Based Optical Pickups

et al. 2007

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“…In [17], we show a simple model for calculating the torque of our vertical combdrive structures etched in multi-level approach [8] out of the same monolithic silicon substrate. As seen in (1), torque (τ) is proportional to the square of the voltage (V) applied between opposing fingers, and to the derivative of comb finger capacitance(C) with respect to angle (θ) which is essentially the tunable capacitance of the combdrive:…”

Section: Torque Improvement -Permittivitymentioning

confidence: 99%

“…v v Figure 1 Gimbal-less two-axis MEMS mirrors: a) Multi-level beam vertical combdrive [8] close-up b) MEMS mirrors of 4.2mm diameter in connectorized packages during production [1], c) Tracking application where a MEMS mirror is pointing a laser beam at the small corner-cube reflector held by a person and can track all human movements [6].…”

Section: Gimbal-less Two-axis Quasistatic Mems Mirrorsmentioning

confidence: 99%

Novel fluidic packaging of gimbal-less MEMS mirrors for increased optical resolution and overall performance

Milanović¹,

Kasturi²,

Yang³

2016

SPIE Proceedings

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Gimbal-less two-axis quasistatic MEMS mirrors have the ability to reflect optical beams to arbitrary positions and with arbitrary velocity. This technology has become established in many applications including laser based tracking, 3D scanning, biomedical imaging, free-space communication, and LiDAR. However, for certain defense applications, the total angle × diameter product, or the mirror's effective achievable resolution (θ*D product), has not been large enough to address requirements for agile steering in large fields of regard and with a low diffraction-limited beam divergence. Two key limitations have been the relatively low forces available in electrostatic combdrive actuators and the susceptibility of large-diameter MEMS mirrors to shock and vibrations. In this work, we demonstrate that these same MEMS mirrors can have dramatically increased performance when fully immersed and packaged in dielectric liquids with highly favorable torque-increasing, damping-increasing, and optical gain-increasing properties. The rotating electrostatic combdrive has its torque multiplied by liquid's relative permittivity of ~2.5. Furthermore, by selecting the appropriate fluid viscosity, quality factor of the device is reduced and structural damping is tuned to near critical damping. Finally, the increased scan angle due to the ~1.5-1.7 index of refraction of the fluid is an additional benefit. These numerous benefits of the fluidic packaging enabled us to double and in some cases triple the previously achieved θ*D product of two-axis quasistatic MEMS mirrors while still maintaining speeds applicable for above mentioned applications. One of the most exciting benefits of the packaging methodologies is that the damping dramatically increases shock and vibration tolerance, which will be tested next.Keywords: MEMS Mirrors, dielectric fluids, dielectric liquid, oil capacitor, electrostatic combdrive, MEMS damping, squeeze film damping. INTRODUCTION Gimbal-less two-axis quasistatic MEMS mirrorsMost of our gimbal-less MEMS mirror device types are designed and optimized for point-to-point optical beam steering. A steady-state analog actuation voltage results in a steady-state analog angle of rotation of the micromirror. Near DC, there is a one-to-one correspondence of actuation voltages and resulting angles: it is highly repeatable with no measurable degradation over time. A sequence of actuation voltages results in a sequence of mirror angles for point-topoint beam-steering. These devices can be operated over a very wide bandwidth from DC (maintaining position at constant voltage with nearly zero power consumption at the device) to several thousand Hertz with mechanical tilt range of -5° to +5° on each axis or larger depending on the design [1]. At higher frequencies closer to device resonance, the full device response must be taken into account; however, it can be generally stated that this technology enables arbitrary control of laser beam position and velocity up to a certain velocity limit. Such fast and broadband capa...

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“…MEMS-based scanning micromirrors using various actuation mechanisms have been demonstrated including piezoelectric, thermal, electrostatic, and electromagnetic actuation (Yasuda et al 2006;Tani et al 2004;Sinclair 2002;Krishnamoorthy et al 2003;Milanović 2004;Hah et al 2004;Kim et al 2009;Yalcinkaya et al 2006). Piezoelectric and thermal actuation can achieve a large force density with low actuation voltage.…”

Section: Introductionmentioning

confidence: 97%