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Progress in Photovoltaics Research and Applications 10/2010; 19(7):772 - 780. · 5.79 Impact Factor
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ABSTRACT: This paper presents the different processing steps of a new generic surface micromachining module for MEMS hermetic packaging at temperatures around 180°C based on nickel plating and photoresist sacrificial layers. The advantages of thin film caps are the reduced thickness and area consumption and the promise of being a low-cost batch process. Moreover, sealing happens by a reflow technique, giving the freedom of choosing the pressure and atmosphere inside the cavity. Sacrificial etch holes are situated above the device allowing shorter release times compared to the state-of-the-art. With the so-called over-plating process, small etch holes can be created in the membrane without the need of expensive lithography tools. The etch holes in the membrane have been shown to be sufficiently small to block the sealing material to pass through, but still large enough to enable an efficient release.
Microsystem Technologies 06/2007; · 0.93 Impact Factor
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M. Gromova,
L. Haspeslagh,
A. Verbist,
B. Du Bois,
R. Van Hoof,
B. Eyckens,
B. Sijmus,
I. De Wolf,
V. Simons,
P. Mutter,
T. Lauwagie,
M. Willegems,
S. Locorotondo,
W. Boullart, K. Baert,
A. Witvrouw
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ABSTRACT: This paper presents very reliable and stable micro- mirrors made of hydrogenated microcrystalline SiGe (muc-SiGe:H) at temperatures that would allow processing above standard CMOS circuitry. Very flat micro-mirrors with sizes ranging between 7.5 x 7.5 and 16 x 16 mum<sup>2</sup> size and submicron hinges are fabricated. No hinge creep is observed over a period of 20 days and no fatigue damage is seen after 5 x 10<sup>10</sup> cycles.
Micro Electro Mechanical Systems, 2007. MEMS. IEEE 20th International Conference on; 02/2007
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CoRR. 01/2007; abs/0711.3317.
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ABSTRACT: Poly-SiGe offers an attractive alternative for low temperature MEMS postprocessing above CMOS. This paper illustrates this fact through several investigations made to obtain a material with excellent mechanical properties (low stress, low stress gradient), and electrical properties (low resistivity) for different structural layer thicknesses and deposition techniques. It was also established that these layers are stable with time and temperature variation, thus ensuring long-term stability in the performance of poly-SiGe based MEMS devices.
Solid-State Sensors, Actuators and Microsystems, 2005. Digest of Technical Papers. TRANSDUCERS '05. The 13th International Conference on; 07/2005
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ABSTRACT: This paper describes two novel processes for depositing poly-SiGe films at CMOS-compatible temperatures (≤450°C). A range of deposition temperatures is investigated to ensure compatibility with different CMOS generations. While the multilayer process investigates temperatures ranging between 420-450°C, the microcrystalline SiGe deposition has been made possible at temperatures as low as 300°C. These films are optimized to obtain low stress and stress gradient values suitable for MEMS structural layers. Low SiGe-Al contact resistivity on the order of 10<sup>-7</sup> Ω.cm<sup>2</sup> and film resistivity as low as 1 mΩ.cm were achieved as well.
Micro Electro Mechanical Systems, 2004. 17th IEEE International Conference on. (MEMS); 02/2004
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ABSTRACT: This paper reports on the experimental determination of the
maximum post-process annealing temperature for standard 0.35 μm CMOS
wafers with aluminum based interconnections and tungsten plugs, without
introducing significant modifications to their standard characteristics.
The impact of increasing the post-processing temperature from 475°C
to 575°C, for periods varying between 30 and 90 min, on both the
front and back end is analyzed. 0.35 μm CMOS technologies with
different Al alloys, Al-1wt%Si-0.5wt%Cu (AlSiCu) or Al-0.5wt%Cu (AlCu),
and different back end structures are considered. It is illustrated that
the maximum annealing temperature is a function of the structure and
composition of the interconnection layers and their maximum allowable
resistance increase. It is also demonstrated that the transistor
characteristics, the silicide quality and the leakage currents are as
good as unaffected by annealing for 90 min at temperatures up to
525°C
IEEE Transactions on Electron Devices 03/2001; · 2.32 Impact Factor
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ABSTRACT: Nanoscaled interdigitated electrodes (IDEs) are being developed for the realization of miniaturized and highly-sensitive affinity biosensors. Until now, nanoscaled IDEs have been realized on silicon wafers using deep UV lithography or e-beam patterning. However, for many applications in the biochemical field there is a strong need for cheap and/or disposable sensor devices. Therefore, a new, cost effective fabrication method for nanoscaled IDEs, which can also be applied on cheap, micro-moulded plastic substrates, has been developed. The method is based on the directionality of a vacuum evaporation process and omits expensive lithography steps completely. The feasibility of this electrode deposition technique has been proven by realizing IDEs on silicon substrates. Future work is focused on the realization of IDEs on injection moulded plastic substrates.
Journal of Micromechanics and Microengineering 07/2000; 10(3):N1. · 2.11 Impact Factor
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A. Witvrouw,
F. Van Steenkiste,
D. Maes,
L. Haspeslagh,
P. Van Gerwen,
P. De Moor,
S. Sedky,
C. Van Hoof,
A. C. de Vries,
A. Verbist,
A. De Caussemaeker,
B. Parmentier, K. Baert
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ABSTRACT: In many applications up to millions of sensors or actuators have to be interconnected to each other and/or to the outside
world, making the monolithic integration of circuitry mandatory. This monolithic integration is also pursued for mass-produced
transducers because of economical reasons. CMOS-integrated transducers are thus found in imaging transducers arrays and mass-produced
physical sensors. In addition, integrated biochemical sensor arrays can be CMOS-integrated.
In this article first a general overview of the field is given and then selected work in the imaging and biochemical field
is highlighted. Concerning imaging transducer arrays an overview is given of visible and IR imagers, displays and of inkjet
printheads. Concerning the new field of biochemical sensor arrays, two examples are described: a blood-gas sensor and an array
of interdigitated electrodes. Finally an overview of the possible technological approaches regarding integrated processing
of transducers is presented.
Microsystem Technologies 01/2000; 6(5):192-199. · 0.93 Impact Factor
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ABSTRACT: In this work, poly SiGe is proposed as a suitable material for surface micromachining applications that require a low thermal budget. The effect of the deposition conditions and layer thickness on the structural and mechanical properties of poly SiGe is analyzed by means of transmission electron microscopy (TEM) and X-ray diffraction spectroscopy (XRD). It is demonstrated that using as-grown poly SiGe (deposited at 625°C), a low tensile stress (+60 MPa) and a negligible stress gradient can be achieved.
Microelectronics, 1999. ICM '99. The Eleventh International Conference on; 12/1999
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ABSTRACT: In this paper, we present a complete characterization of poly SiGe
bolometers. Devices having different dimensions and different geometry
have been fabricated. The dependence of the low-frequency noise and of
the temperature coefficient of resistance (TCR) on resistivity in poly
SiGe has been measured and modeled. The impact of resistivity, bias
voltage, thermal conductance, thickness, and dimensions of the active
element on the device performance has been investigated. It has been
demonstrated that, by using the appropriate absorber and by optimizing
the device parameters, poly SiGe bolometers are suitable for realizing
high-performance focal plane arrays (FPA's)
IEEE Transactions on Electron Devices 05/1999; · 2.32 Impact Factor
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ABSTRACT: In this paper, we propose polycrystalline silicon germanium (poly
SiGe) as a material suitable for MEMS applications. Films are prepared
by chemical vapor deposition (CVD) at atmospheric pressure (AP) or
reduced pressure (RP). The structure of the films is investigated by
X-ray diffraction (XRD) and transmission electron microscopy (TEM) for
different deposition and annealing conditions. The stress in the
as-grown and annealed layers is measured, and the correlation between
stress and structural properties is discussed. It is demonstrated that
by adjusting the deposition conditions, the stress of the as-grown
material can be varied from -145 to 60 MPa. Examples of poly SiGe
micromachined devices, prepared at 650°C, are presented. It is shown
that by using as-grown poly SiGe, it is possible to realize
surface-micromachined suspended membranes having 0.6-μm-wide and
50-μm-long supports. The effect of the average stress and stress
gradient on the mechanical stability of surface-micromachined structures
is illustrated. Finally, the strain in poly SiGe is measured, and it is
found to vary, according to the deposition conditions from
-6.88×10<sup>-4</sup> to 3.6×10<sup>-1</sup> These values
are compared to those measured for APCVD poly Si
Journal of Microelectromechanical Systems 01/1999; · 2.10 Impact Factor
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ABSTRACT: A novel device for controlling the radiative transfer of heat is proposed. An Active Radiator tile (ART) is composed of two parallel plates separated by small thermally insulating posts. In the rest state, the ART presents a large thermal resistance. Application of a suitable potential across the plates causes one plate to deflect into direct contact with other plate, allowing a large conductive heat flow. Thus the ART device acts as a thermal valve. We report the modelling of the mechanical and thermal properties of the device, and progress towards the construction of a laboratory prototype.
Journal of Micromechanics and Microengineering 12/1998; 5(2):186. · 2.11 Impact Factor
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ABSTRACT: An integrated silicon strain gage for multi-axial measurements is proposed. The device contains p-type strain gages oriented along orthogonal directions. For reasons of compactness, a particular geometry was developed. The strain gages are located on thinned silicon beams, which are suspended in a support with an octagonal shape. This shape was achieved by micromachining structures along edges as well as along edges.
Journal of Micromechanics and Microengineering 12/1998; 6(1):84. · 2.11 Impact Factor
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ABSTRACT: We present a micromachined infrared IR detector based on the principle of the Golay cell. The detector basically consists of a sealed cavity, in which the heat generated by absorbed in light results in an increased gas pressure. This pressure rise is detected capacitively. The theoretical responsivity and noise equivalent of a micromachined device are calculated, and it is shown that a detectivity of 3.6*109 cm Hz1/2 W-1 can be expected for a 1 mm2 micromachined version. Further, we propose the use of a micromachined pneumatic gas leak in order to avoid thermal drift. A prototype was fabricated using Si and Pyrex micromachining techniques, and confirmed the principle of operation. The preliminary experimental results are compared to theory.
Journal of Micromechanics and Microengineering 12/1998; 5(2):193. · 2.11 Impact Factor
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ABSTRACT: In many applications, up to millions of sensors or actuators have
to be connected to the outside world, making the monolithic integration
of circuits mandatory. Monolithic integration is also pursued for
mass-produced transducers. Today, monolithic devices include visible and
IR imagers, displays, inkjet heads, biochemical and physical sensors.
Monolithic integration of transducer-specific processes (such as
micromachining) with standard CMOS processes is possible, albeit at an
increase of process complexity
ASIC Conference 1998. Proceedings. Eleventh Annual IEEE International; 10/1998
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ABSTRACT: This paper reports on a novel micromachining technique for
fabricating rubber membranes with an area of tens of square centimetres
and a thickness of a few micrometers. In the basic technique a silicon
wafer is spincoated with liquid rubber, bonded to a second (sacrificial)
wafer and locally thinned out by anisotropical wet etching. The
potential of the technique is highlighted in a demonstration example
where a 20 cm<sup>2</sup> large biocompatible membrane is used to
mechanically support and thermally isolate a large active area
thermopile in a microcalorimeter for medical use
Solid State Sensors and Actuators, 1997. TRANSDUCERS '97 Chicago., 1997 International Conference on; 07/1997
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ABSTRACT: Nanoscaled interdigitated electrode arrays were made with Deep
U.V. lithography. Electrode widths and spacings from 500 nm down to 250
nm were achieved on large active areas (0.5 mm×1 mm). These
electrodes allow for the detection of affinity binding of biomolecular
structures (e.g. antigens, DNA) by impedimetric measurements. Such a
sensor is developed, theoretically analyzed, experimentally
characterized, and is demonstrated as an affinity biosensor
Solid State Sensors and Actuators, 1997. TRANSDUCERS '97 Chicago., 1997 International Conference on; 07/1997
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Solid-State Sensors and Actuators, 1995 and Eurosensors IX.. Transducers '95. The 8th International Conference on; 07/1995
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Solid-State Sensors and Actuators, 1995 and Eurosensors IX.. Transducers '95. The 8th International Conference on; 07/1995
