Eric Lebrasseur

A new characterization tool for vertical profile measurement of high-aspect-ratio microstructures

We have developed a system for the measurement of the inner profile of high-aspect-ratio microstructures. This system uses silicon micro-probes with a sharp tip at their end and an integrated piezoresistive force sensor. The probes are 1 mm long with a cross-sectional area of 20 × 20 μm2, which allowed characterization of narrow and deep micro-holes having a radius as small as 40 μm. The measurement procedure utilizes an original algorithm, which prevents it from many unwanted phenomena. It is entirely automated by using a computer control.

Integration of two degree-of-freedom magnetostrictive actuation and piezoresistive detection: application to a two-dimensional optical scanner

A novel two-dimensional (2-D) optical-scanner device is presented. This device incorporates a highly magnetostrictive thin film with anisotropic properties, so that it can produce 2-D-actuation corresponding to bending and torsion vibrations. The magnetostrictive material is a TbFe-CoFe multilayer film, which has optimized properties for micro-actuators operating at low excitation magnetic fields. The new scanner also integrates an original 2-D piezoresistive detector realized in an easy fabrication process using integrated circuit (IC)-compatible technology. The detectors are able to selectively measure bending and torsional vibrations. This new device enables the synchronization of actuation and sensing for 2-D position control.

An apparatus for electric-field-induced protein crystallization

A new device has been fabricated for electric field-induced protein crystallization with the microbatch method. In conjunction with this, a specialized tray using inexpensive plastic film has been developed for economical set-up of the experiments. Crystallization can be conducted using AC or DC voltage.

Protein crystallization under an electric field

New methods for improving the quality of protein crystals are always being sought. Electric-field-induced protein crystallization is one of them. A few devices have already been developed. We conducted a series of experiments for several years and fabricated many electrode panels to realize a device for electric-field induced protein crystallization for the microbatch method. The review mainly deals with the application of the various devices that have so far been reported in the literature on the subject, including an overview of the work that has already been conducted. The factors affecting the electric-field-induced protein crystallization are also discussed.

A heat balanced sigma–delta uncooled bolometer

This paper describes a heat balanced bolometer with an integrated CMOS sigma–delta interface. The sigma–delta interface accomplishes both the analogue-to-digital conversion and the heat feedback and therefore no other digital core is required. The heat feedback is implemented using a capacitively coupled electrical substitution technique with a digitally modulated signal that enables feedback linearization. Proof of concept is experimentally demonstrated with a polymer-type resistive bolometer and infrared optical source.

Independent light-trapping cavity for ultra-sensitive plasmonic sensing

The sensing characteristics of an independent-plasmonic-cavity structure that traps light were investigated. The cavity structure traps light by generating self-contained optical vortices in each independent cavity without leakage or propagation of the light; therefore, strong and sharp resonance dips are obtained in a reflectance spectrum. Multiple optical vortices are generated in the independent cavities in higher-order plasmonic cavity modes at shorter wavelengths, realizing the resonance in a wide range from visible to near-infrared. Compared to the propagating surface plasmon resonance, the resonance of plasmonic cavity mode in the independent cavity does not depend on variation of the incident angle of light. The independent-cavity structure was fabricated by a simple process, and it experimentally demonstrated a high sensitivity (above 1500 nm per refractive index unit) and a figure of merit above 20.

Discharging-phototransistor-integrated high-voltage Si photovoltaic cells for fast driving demonstration of an electrostatic MEMS actuator by wavelength modulation

In this article, the authors propose a high-voltage photovoltaic (PV) cell array integrating discharging phototransistors for the fast driving of an electrostatic MEMS actuator by light with wavelength modulation. A PV cell array and phototransistors are connected in parallel and colored with green and red lacquer, respectively. This circuit repeats the charge and discharge of a MEMS actuator by being illuminated with light whose color periodically changes between red and green. This method requires only a small additional area and can discharge the actuator at an arbitrary timing. The authors extract the parameters of the circuit and also demonstrate the dynamic driving of a MEMS comb-drive actuator.

Remote power feed and control of MEMS with 58 V silicon photovoltaic cell made by a CMOS post-process dry release and device isolation method

A small autonomous device integrating MEMS, CMOS and photovoltaic (PV) cells has many attractive applications. For such a device, using light as a power source is preferable because power feeding and control signal transmitting can be done at the same time and in a remote manner. We demonstrated the remote power feeding to a MEMS actuator by light using PV cell array. In this article, we first proposed a new dry release method of MEMS structure for a CMOS-MEMS-PV integration. The method does not require vapor HF and thus we can avoid damage to CMOS circuits. We demonstrated the method by releasing MEMS cantilevers. Next, we prepared a PV cell array integrable with CMOS and MEMS. Its open circuit voltage was 58 V and its maximum power was 43.3 μW. We conducted an experiment to drive a MEMS comb drive actuator remotely, irradiating laser light from the distance of 1.5 m. The PV cell array successfully fed power and the actuator moved 1.0 μm, two-thirds of the calculated value.

Microsystem for Vertical Profile Measurement of High Aspect-ratio Microstructures

We have developed a microsystem for measurement of inner profile of high aspect-ratio microstructures. This system uses silicon micro-probes with a sharp tip at their end and an integrated piezoresistive force sensor. The probes are 1mm-long with a cross-section area of 20×20µm2, which allowed the characterization of narrow and deep micro-holes having a radius as small as 40µm. The measurement procedure utilizes an original algorithm, which prevents from many unwanted phenomena. It is entirely automated by using a computer control.

Microsystem tool for microsystem characterization profile measurement of high-aspect-ratio microstructures

A microsystem for the measurement of profiles of high aspect-ratio microstructures has been developed. This microsystem uses a silicon micro-probe with a sharp tip at its end and an integrated piezoresistive strain gauge force sensor. The probes are from 500 micrometers to 1 mm long with a cross-section of 20x20micrometers 2; they were previously mainly designed for the characterization of narrow and deep micro-holes having a radius as small as 50micrometers . The profile measurement method has been extended to the characterization of other microstructures. In a first part of this paper, we explain the method based on an original algorithm to measure profiles with the greatest precision and reproducibility. In a second part we give some information about the capabilities for horizontal and vertical profiles measurement, concave and convex surfaces profiles plotting. We conclude with some experimental results for several types of profiles.