SiGe based grating light valves: A leap towards monolithic integration of MOEMS

Rudra, S.; Roels, Joris; Bryce, George; Haspeslagh, L.; Witvrouw, Ann; Thourhout, Dries Van

doi:10.1016/j.mee.2009.12.015

Cited by 6 publications

(6 citation statements)

References 10 publications

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“…We used a 405 nm violet laser to characterize the optical response of the GLVs and to estimate the maximum contrast achievable for the devices. The dark state noise obtained in the non-actuated state is much lower compared to our previous reported work [3]; mainly due to the improved flatness among consecutive microbeams. For the current devices, a maximum contrast of ~ 1530:1 was obtained reproducibly showing the usefulness of our GLVs in making high quality displays.…”

Section: Resultscontrasting

confidence: 64%

Static and dynamic characterization of pull-in protected CMOS compatible poly-SiGe grating light valves

Rudra

Coster

Hoof

et al. 2012

Sensors and Actuators A: Physical

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Grating Light Valve (GLV) display pixels are reflection type diffraction gratings consisting of electrostatically movable coplanar microbeams. Once actuated, the alternate movable beams deflect downwards which produces controlled diffraction of light creating bright and dark pixels in a display system. GLV displays provide a huge improvement in contrast ratio and resolution over other MOEMS devices. At the same time, compared to hybrid integration, post processing of MEMS monolithically on top of CMOS can lead to increased functionality, performance and reliability. Poly-SiGe structural layers can be deposited at low temperature (~450°C), allowing to retain the performance of underlying CMOS electronics though possessing the desired material properties for MEMS. Hence the aim of this work is to fabricate CMOS compatible poly-SiGe GLVs and to study their static and dynamic behavior. A novel process flow was developed regarding the deposition of thin poly-SiGe structures which is well within the maximum thermal range to retain the full functionality of the underlying CMOS circuitry. A contrast of over 1500:1 was obtained showing excellent optical response of the devices. The effect of squeeze film damping in determining the dynamic response of the GLVs is thoroughly investigated. Influence of variation in dimensional parameters on the settling time of the structures is discussed in detail. A minimum settling time of 2 µs was achieved for our devices. We also showed the analog gray scale nature of the GLVs. In addition, we also use the technique of mechanical stoppers to avoid accidental destruction of the devices because of the pull-in phenomenon.

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Section: Resultscontrasting

confidence: 64%

Static and dynamic characterization of pull-in protected CMOS compatible poly-SiGe grating light valves

Rudra

Coster

Hoof

et al. 2012

Sensors and Actuators A: Physical

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“…Resonance frequencies of 920kHz, 255kHz and 124kHz were found respectively for the 50, 100 and 200 μm beams (15).…”

Section: Resultsmentioning

confidence: 90%

(Invited) SiGe MEMS Technology: A Platform Technology Enabling Different Demonstrators

Witvrouw¹,

Hoof²,

Bryce³

et al. 2010

ECS Trans.

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In imec's 200mm fab a dedicated poly-SiGe above-IC MEMS (Micro Electro-Mechanical Systems) platform has been set up to integrate MEMS and its readout and driving electronics on one chip. In the Flemish project Gemini the possibilities of this platform have been further explored together with the project partners. Three different demonstrators were realized: mirrors for display applications, grating light valves (GLV) and accelerometers. Whereas the mirrors and GLVs are made with a ~300 nm thick SiGe structural layer plus optical coating, the SiGe structural layer thickness for the accelerometers is 4µm in order to improve the capacitive readout of in-plane devices. The processing and measurement results of these functional demonstrators are shown in this paper. These new demonstrators reconfirm the generic nature of the SiGe MEMS platform.

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“…The GLV device has also been fabricated with other materials, such as poly-SiGe, by taking advantage of CMOS-integrated MEMS technology. [102] Such GLV device could achieve good tuning behavior under a 16 V driving voltage, and the resonant frequency was reported to be 90 kHz for the ribbon with 50 mm width. In Ref.…”

Section: Mems Gratings With Tunable Profilementioning

confidence: 99%

MEMS gratings and their applications

Zhou

Lim

et al. 2021

International Journal of Optomechatronics

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Grating plays an essential role in various optical systems owing to its unique dispersion properties. In recent years, there is increasing demand to miniaturize optical systems for a wide range of field applications. Therefore, the integration of diffraction grating with MEMS technology provides an efficient way to build truly miniaturized optical systems. Till now, MEMS diffraction gratings have mainly been explored in two directions, namely MEMS scanning gratings and MEMS tunable gratings. MEMS scanning gratings are constructed with a variety of MEMS actuators to drive a grating platform to scan across the target, and they play a significant role in various scanning systems. Meanwhile, the dispersive properties of grating scanners make them attractive in wavelength sensing applications, including spectrometers and hyperspectral imaging systems. Tunable gratings typically employ MEMS actuators to dynamically change the diffraction properties, thus tuning its wavelength sensitivity for a specific application. Thus, this review will introduce these two types of MEMS gratings in detail and evaluate their efficiency and advantages in various fields.

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SiGe based grating light valves: A leap towards monolithic integration of MOEMS

Cited by 6 publications

References 10 publications

Static and dynamic characterization of pull-in protected CMOS compatible poly-SiGe grating light valves

Static and dynamic characterization of pull-in protected CMOS compatible poly-SiGe grating light valves

(Invited) SiGe MEMS Technology: A Platform Technology Enabling Different Demonstrators

MEMS gratings and their applications

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