CMOS compatible polycrystalline silicon–germanium based pressure sensors

Gonzalez, Pilar; Guo, Baofeng; Rakowski, Michal; Meyer, K. De; Witvrouw, Ann

doi:10.1016/j.sna.2011.12.018

Cited by 19 publications

(7 citation statements)

References 9 publications

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“…This total period is calculated by adding the times required for the different poly-SiGe depositions and annealing steps, as these are the operations requiring the highest temperature. This total time is significantly lower than the maximum time of 6 hours at 455Û C which was tested for a Cu-based 0.13 µm CMOS process [19] and was found not to degrade the underlying CMOS functionality. Hence, we can conclude that the GLV devices are fully compatible for processing on top of CMOS.…”

Section: Fabrication Of Glvsmentioning

confidence: 79%

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: Fabrication Of Glvsmentioning

confidence: 79%

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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“…Compared with other pressure sensors, the capacitive pressure sensor shows some significant advantages such as high sensitivity, low power, low noise and low temperature drift coefficients [ 2 ]. Recently different types of capacitive pressure sensor were reported [ 1 , 2 , 3 , 4 , 5 ], but these designs don’t integrate any signal processing circuits, resulting in increasing parasitic capacitance and lowering sensor performance.…”

Section: Introductionmentioning

confidence: 99%

A CMOS Pressure Sensor Tag Chip for Passive Wireless Applications

Deng

et al. 2015

Sensors

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This paper presents a novel monolithic pressure sensor tag for passive wireless applications. The proposed pressure sensor tag is based on an ultra-high frequency RFID system. The pressure sensor element is implemented in the 0.18 µm CMOS process and the membrane gap is formed by sacrificial layer release, resulting in a sensitivity of 1.2 fF/kPa within the range from 0 to 600 kPa. A three-stage rectifier adopts a chain of auxiliary floating rectifier cells to boost the gate voltage of the switching transistors, resulting in a power conversion efficiency of 53% at the low input power of −20 dBm. The capacitive sensor interface, using phase-locked loop archietcture, employs fully-digital blocks, which results in a 7.4 bits resolution and 0.8 µW power dissipation at 0.8 V supply voltage. The proposed passive wireless pressure sensor tag costs a total 3.2 µW power dissipation.

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“…In order to improve the sensor performance, the surface micromachined pressure sensors have been developed which contain dioxide silicon sacrificial layers, a polysilicon diaphragm and standard polysilicon thin film piezoresistors. The sensors have the advantages of small size, high sensitivity, process compatible with that of integrated circuits [2,3] and good temperature characteristics [4]. However, polysilicon based pressure sensors in general have lower sensitivity than diffusion silicon based pressure sensors due to the lower gauge factor of standard polysilicon thin films [5,6].…”

Section: Introductionmentioning

confidence: 99%