Surface Image Analysis in Scanning Probe Microscopy

W pracy przedstawiono wybrane metody analizy powierzchni (ISO 25178) wskazując na rodzaj informacji, jaką można za pomocą danej metody uzyskać. Opisywane algorytmy i procedury zostały zaimplementowane w opracowanym w Wydziałowym Zakładzie Metrologii Mikro- i Nanostruktur Politechniki Wrocławskiej programie TOPOGRAF. W pracy zaprezentowano przykładowe wyniki działania zaimplementowanych algorytmów i procedur.Progress in the scanning probe microscopy makes it become a much more common tool. In the paper the principle of operation of the scanning probe microscope is presented. It is emphasized that the measurement result is an image of the investigated surface. Two groups of parameters connected with lateral properties of the tested surface image are introduced. The first group of parameters is connected with the image autocorrelation function and two dimensional Fourier transform. The texture aspect ratio and surface autocorrelation length (Fig. 1) are given as examples of the autocorrelation parameters. The second group of parameters is related to the so called 3D motif analysis. At the first stage of this analysis the image is segmented by means of the watershed segmentations algorithm. At the second stage the statistics connected with the shape and dimensions of the segments are calculated. The segmentation algorithm as well as the parameters describing shape and dimensions of segments (Fig 2) are presented in the paper. Due to the quantum nature of the micro- and nano-world, the uncertainty of products of the micro and nanotechnology will always be greater than that of products of the conventional technology. For this reason there is strong demand for flexible techniques capable of handling this increased uncertainty. The 3D motif analysis is very well suited to meet this challenge, since it enables the extension of the basic set of the parameters describing segments. Therefore the segment parameters might be adapted to the function of the investigated nanostructures. The images presented in the paper were obtained by means of the TOPOGRAF software that is developed at the Division of Micro- and Nanostructures Metrology

Application of scanning shear-force microscope for fabrication of nanostructures

In view of the rapid growth of interest in AFM technique in surface property investigation and local surface modification we describe here an AFM microscope with optical tip oscillation detection. The modular shear-force/tunneling microscope for surface topography measurement and nanoanodisation is described. The measurement instrument presented here is based on the fiber Fabry-Perot interferometer for the measurement of the conductive microtip oscillation that is used as nano e-beam for local surface anodisation. An advantage of this system is that quantitative measurements of tip vibration amplitude are easily performed

Adsorption properties of porous silicon

Porous silicon shows some interesting features for micromechanical applications. Some applications make use of its high surface-to-volume ratio. A capacitive gas or humidity sensor using the adsorption of gases on the porous surface can be easily fabricated. However an opportunity for more sensitive device is given by micromechanical structure. In this paper we report on the piezoresistive cantilever beam structure with porous silicon adsorbing spot as a gas sensor

Wide-band optical fibre system for investigation of MEMS and NEMS deflection

In this work the construction of experimental setup for MEMS/NEMS deflection measurements is presented. The system is based on intensity fibre optic detector for linear displacement sensing. Furthermore the electronic devices: current source for driving the light source and photodetector with wide-band preamplifier are presented

Atmospheric Pressure Plasma Jet for Mass Spectrometry

The atmospheric pressure plasma is much advantageous over low pressure plasmas in various aspects, e.g. vacuum-free operation, relative low cost, flexibility of a continuous process. Among various plasmas generated in atmospheric pressure discharges there are cold plasma jets that represent a technology of great application promise (industry, medicine, biology). To generate low-temperature plasmas at atmospheric pressure the dielectric barrier discharge can be used. It is suitable for the atomization of volatile species and can also be served as a ionization source for ambient mass and ion mobility spectrometry. As the discharge is generated in a restricted electrode structure, a plasma jet (plume) is usually formed outside the electrode region (that provides spatial separation of the plasma generation and surface processing regions). The paper presents a source based on a plasma jet established at the end of a capillary dielectric barrier discharge at atmospheric pressure and its application to mass spectrometry. The structure of the jet generator consists of piezoelectric transformer and two concentric and symmetric electrodes, between which the working gas flows at definite rate. Besides the source description early results of spectroscopic analysis are also given

Quantum mechanical aspects in the MEMS/NEMS technology

According to the scaling laws for nanomechanical resonators, many of their metrological properties improve when downscaled. This fact encourages for constant miniaturization of MEMS/NEMS based sensors. It is a well known fact, that the laws of classical physics cannot be used to describe the systems which are arbitrarily small. In consequence, the classical description of nanoresonators must break down for sufficiently small and cool systems and then the quantum effects cannot be neglected. One of the fundamental question which arises is, how one may investigate quantum effects in MEMS/NEMS sensors and what is the influence of quantum effects on the performance of such systems. In this paper we would like to raise those issues by presenting the results of our work related to our estimations and calculations of MEMS/NEMS dynamics. The first and second sections are of theoretical character. In the first section (Classical modeling), we describe the classical methods for describing the resonator dynamics and the classical limit on the resolution of MEMS/NEMS based force sensors, which is set by the thermomechanical noise. In the second section (Quantum aspects), we concentrate on the quantum description of micro and nanoresonators and the influence of quantum effects, such as zero-point motion and back-action, on their performance (quantum limits). The third section is devoted to the presentation of our experimental methods of MEMS/NEMS deflection metrology, i.e. Optical Beam Deflection method (OBD) and fibre optics interferometry