Raphael Foschia

Versatile force–feedback manipulator for nanotechnology applications

A nanoscale manipulation system has been designed and built through the integration of a force–feedback haptic device and a commercial atomic force microscope. The force–feedback interaction provides a very intuitive, efficient and reliable way for quick manipulation of nanoscale objects. Unlike other nanomanipulators, ours allows the user to feel the actual tip–sample interaction during the manipulation process. Various modes of manipulation have been implemented and evaluated. As a proof of concept, we show a contact-mode nanomanipulation of a carbon nanotube and a noncontact manipulation of silicon beads. In addition to nanomanipulation itself, all relevant signals can be recorded during the manipulation process which allows quantitative interpretation of nanomechanics experiments.

Local dynamic mechanical analysis.

While new materials with tailored properties appear every day, the need of appropriate characterization tools is still an important concern. Analyses of thin films on thick substrate are often highly influenced by the substrate properties. A dynamical nanoindentation system has been designed and built through the integration of a nanoindenter head equipped with capacitive displacement sensing, scanning probe microscope with related XYZ scanning electronics and an additional transducer for sample actuation. Our Local-Dynamic Mechanical Analysis (L-DMA) setup allows for both, tip and sample modulation mode what somehow contrasts with commercially available systems. This issue allows for direct comparison between both techniques and therefore for consistent quantitative mechanical measurements. The system offers two distinctive measurement techniques, local mechanical spectroscopy and mechanical imaging modes. Bulk materials as well as thin films of ceramics and polymers have been used for testing and validating the setup. The instrument has been modeled in sample modulation mode and experimental results obtained for different materials were compared with simulation data.

Nanometrology for MEMS : combination of optical interference, atomic force microscopy and nanoindentor-based actuator

We show the integration of a home-made interference optical microscope (IOM) with an Atomic force microscope, as well as the combination of IOM with a nanoindentor. Such combined instruments have many applications in the characterisation of MEMS/NEMS. As an illustrative example, we have used a MEMS accelerometer with capacitive read-out. Surface topography and defects have been measured with an IOM/AFM setup, as well as the bending and the torsion of the inertial mass while a calibrated force is applied with the nanoindentor probe on an off-axis location of the inertial mass.

Nano‐scale Force Feedback Manipulator

A description of the instrumental requirements for AFM‐based nanomanipulation system is presented, as well as the design, the features and the benefits of our force feedback nano‐scale manipulator. The description covers as well some software aspects for quick and successful nano‐manipulation. As an illustration, cross sectioning of carbon nanotube (CNT) and WS2 nanotubes are shown.

Force Modulation and Dynamic NanoIndentation Microscopy

We have made a Dynamic Nanoindentation Microscope (DNM) setup based on sample modulation, in order to allow a direct comparison between various dynamical mechanical measurement techniques such as Force Modulation Microscopy (FMM) and Dynamic Mechanical Analysis (DMA). The microscope is integrated to a standard Atomic Force Microscope (AFM) and uses a commercial nanoindentation system. Instead of the standard bimorph and force modulation configuration, we used a stacked ceramic sample actuator in displacement modulation. Both DMA measurements and DNM imaging were performed on each sample for the determination of the reduced, storage and loss modules, and a good agreement between the techniques have been found. Compared to FMM, we show that DNM has the advantage of always keeping the same contrast in the viscoelastic images as a function of the frequency.

Data coding tools for color-coded vector nanolithography

We propose and demonstrate the ability and efficiency of using a universal file format for a nanolithography pattern. A problem faced by the physicists working in the field of nanolithography is a lack of a flexible pattern design software (possibly open–source) that could be applied in combination with a broad range of commercial scanning probe microscope (SPM) systems. The current nanolithography software packages are device–specific and not portable. Therefore, it is impossible to make a lithography pattern and share it with fellow physicists working on a networked sub-system. In this paper we describe the software designed to read and interpret a nanolithography pattern stored in a Windows Metafile (WMF) standard graphic format and next to draw it on a substrate using an SPM tip. The nanolithography parameters like height, velocity, feedback force, etc. are coded in the color of the WMF onto the RGB channels of the image establishing a distinct relation between a graphical feature (color) and the used...

Real-Time Interferometric Microscopy in Liquids

We have made a Phase Shift Interferometric Optical Microscope operating in liquid and in real time. As a proof of concept, we show the nano-evolution of a surface profile of Cu in sulphuric acid.

High resolution in interferometric microscopy

Interferometric optical microscopes (IOM) are very powerful 3D metrology tools which use integrated interferometers inside optical objectives. In Phase Shift Mode (PSM) [1], they can reach subnanometer vertical resolution but the lateral resolution, as any far-field optical system, is limited by diffraction to typically 0.5 um. They have a widespread use in microfabrication industries (microelectronics and MEMS).

Use of light-emitting diode (LED) in interference microscopy

We present a systematic investigation of the use of LED as light sources for interference microscopy, in comparison with more standard halogen illumination. For translation height mode (also known as vertical scanning or low coherence microscopy), five white LED-based illuminations setup have been tested, including the use of filters to remove the shoulder in the blue region often encountered in such LED. For the six white light illuminations (five LED plus halogen), we have measured the irradiance spectra and calculated and measured the corresponding correlograms. The influence of the combined effect of the illumination spectra and a dispersive phase shift on the calculated height reconstruction is shown for a center-of-mass algorithm. In phase shift mode, both monochromatic LED and white LED with inteference filters have been used. Blue LED illumination improves the lateral resolution compared to red illumination, a task which can be done with halogen lamp only with very reflecting sample due to its low power in the blue wavelengths. All measurements have been performed with our home-made interference microscope, which is described in Proc. SPIE 6188,61880T (2006).