P. Janus

A high-resolution measurement system for novel scanning thermal microscopy resistive nanoprobes

In this paper, a scanning thermal microscopy (SThM) module with a modified Wheatstone bridge is presented. It is intended to be used with a novel four-terminal thermoresistive nanoprobe, which was designed for performing thermal measurements in standard static-mode atomic force microscopes. The modified Wheatstone bridge architecture is also compared to a Wheatstone bridge and a Thomson bridge in terms of their temperature measurement sensitivities. In fixed conditions, they are found to be (7.05 ± 0.04) μV K−1 for the modified Wheatstone, while (5.43 ± 0.06) μV K−1 for the Wheatstone and (0.91 ± 0.09) μV K−1 for the Thomson bridge. The usability of the three set-ups with four-terminal nanoprobes is also discussed. The design of devices included in the module is presented and the noise level of the modified Wheatstone bridge is estimated. A proportional–integral–derivative controller for active-mode SThM is also introduced.

Microfabricated resistive high-sensitivity nanoprobe for scanning thermal microscopy

In this article, a novel microfabricated thermoresistive scanning thermal microscopy probe is presented. It is a V-shaped silicon nitride cantilever with platinum lines and a sharp off-plane nanotip. The cantilever fabrication sequence incorporates standard complementary metal oxide semiconductor technology processes and therefore provides high reproducibility, while the tip is additionally processed by focused ion beam, enabling high-sensitivity and high-resolution thermal sensing. The nanoprobe is designed for scanning thermal microscopes, operating in standard atomic force microscope setup with an optical detection system. The measurement setup, which is also presented, takes advantage of the four-point design of the probe by inclusion of a Thomson bridge and a modified Wheatstone bridge measurement electronics.In this article, a novel microfabricated thermoresistive scanning thermal microscopy probe is presented. It is a V-shaped silicon nitride cantilever with platinum lines and a sharp off-plane nanotip. The cantilever fabrication sequence incorporates standard complementary metal oxide semiconductor technology processes and therefore provides high reproducibility, while the tip is additionally processed by focused ion beam, enabling high-sensitivity and high-resolution thermal sensing. The nanoprobe is designed for scanning thermal microscopes, operating in standard atomic force microscope setup with an optical detection system. The measurement setup, which is also presented, takes advantage of the four-point design of the probe by inclusion of a Thomson bridge and a modified Wheatstone bridge measurement electronics.

Expanded beam deflection method for simultaneous measurement of displacement and vibrations of multiple microcantilevers

Here we present an extension of optical beam deflection (OBD) method for measuring displacement and vibrations of an array of microcantilevers. Instead of focusing on the cantilever, the optical beam is either focused above or below the cantilever array, or focused only in the axis parallel to the cantilevers length, allowing a wide optical line to span multiple cantilevers in the array. Each cantilever reflects a part of the incident beam, which is then directed onto a photodiode array detector in a manner allowing distinguishing between individual beams. Each part of reflected beam behaves like a single beam of roughly the same divergence angle in the bending sensing axis as the incident beam. Since sensitivity of the OBD method depends on the divergence angle of deflected beam, high sensitivity is preserved in proposed expanded beam deflection (EBD) method. At the detector, each spots position is measured at the same time, without time multiplexing of light sources. This provides real simultaneous readout of entire array, unavailable in most of competitive methods, and thus increases time resolution of the measurement. Expanded beam can also span another line of cantilevers allowing monitoring of specially designed two-dimensional arrays. In this paper, we present first results of application of EBD method to cantilever sensors. We show how thermal noise resolution can be easily achieved and combined with thermal noise based resonance frequency measurement.

Design, technology, and application of integrated piezoresistive scanning thermal microscopy (SThM) microcantilever

In this article we describe a novel piezoresistive cantilever technology The described cantilever can be also applied in the investigations of the thermal surface properties in all Scanning Thermal Microscopy (SThM) techniques. Batch lithography/etch patterning process combined with focused ion beam (FIB) modification allows to manufacture thermally active, resistive tips with a nanometer radius of curvature. This design makes the proposed nanoprobes especially attractive for their application in the measurement of the thermal behavior of micro- and nanoelectronic devices. Developed microcantilever is equipped with piezoresistive deflection sensor. The proposed architecture of the cantilever probe enables easy its easy integration with micro- and nanomanipulators and scanning electron microscopes.In order to approach very precisely the microcantilever near to the location to be characterized, it is mounted on a compact nanomanipulator based on a novel mobile technology. This technology allows very stable positioning, with a nanometric resolution over several centimeters which is for example useful for large samples investigations. Moreover, thanks to the vacuum-compatibility, the experiments can be carried out inside scanning electron microscopes.

Piezoresistive cantilever working in a shear force mode for in situ characterization of exposed micro- and nanostructures

This paper presents a method of characterization micro- and nanostructures defined in a photolithography process. To implement this method a measurement system composed of an atomic force microscope (AFM) integrated with a system for maskless lithography was developed. This integration enables exposed patterns to be examined in situ, without any necessity for a developing process. The microscope works in a shear force mode, uses a cantilever with a piezoresistive method of detecting deflection and can be used for measuring surfaces with high aspect ratio by applying an appropriate technology of sharpening in a focused ion beam process. The cantilever fabrication process, its calibration and examination procedures are presented. Finally, the AFM images of structures scanned directly after exposure are shown.

Modeling and Co-Simulation of Integrated Microand Nanosystems

In this paper we present a system-level, top-down design/modeling methods for microsystem (MEMS) devices. We describe advanced process co-simulation/emulation of MEMS and integrated circuits. The methodology of hardware-in-the-loop basing on co-simulation of MEMS and IC using signal flow simulators is also discussed.

Characterization of fatigued Al lines by means of SThM and XRD: Analysis using fast Fourier transform

Abstract Longitudinal performance and reliability of microelectronic structures is strongly influenced by the condition of interconnects. Degradation processes invoke changes, progressive in time, on the surface, in the body of interconnect layer, in the boundary between interconnect and the Si/SiO 2 substrate, and in the area of substrate near Al line. Geometrical scale of these changes may vary in wide range, reaching nanometers. The authors investigate the condition of Al path of a fatigued commercial electronic circuit (memory), using in-house developed scanning thermal microscope (SThM) and commercial high resolution X-ray diffractometer (XRD). Series of SThM images were obtained for varying temperature of Wollaston probe working in active mode. The images, after processing by 2-dimensional spatial FFT, reveal various ingredients of the surface and internal structure of the Al line. FFT power spectrum dispersion is proposed as a measure of the amount of information available from the scan image. This measure may be used to determine the most efficient temperature of Wollaston probe. The result is a preliminary analysis of feasibility of the SThM approach for characterization of degradation process. In general SThM shall be perceived as a new technique for reliability analysis.

Application of a Scanning Thermal Nano-Probe for Thermal Imaging of High Frequency Active devices

The first application of a new thermal nano-probe based on the changes of electrical resistivity of a nanometer-sized filament with temperature has been presented for the thermal imaging of microwave power active devices. The integration of the filament the fabrication process of the novel thermal probe with a spatial resolution better than 80 nm and a thermal resolution of the order of 10-3 K have already been presented in reference [J. Microelectron. Eng. 57–58 (2001) 737]. To demonstrate the capability of the novel thermal nano-probe the measurements have been successfully performed on a 30 fingers GaAs metal–semiconductor field-effect transistor (GaAs-MESFET) with a maximum power dissipation of 2.5 W. The bias circuit has been designed to suppress the undesired microwave oscillations in the transistor. In this case the power dissipation is equal to the dc power input. The near-field measurements using the nano-probe are compared with infrared measurement and three-dimensional finite element static thermal simulations. The good agreement between simulations and measurements confirms the high capability of the nono-probe for these applications.

Microfabricated support structures for investigations of mechanical and electrical graphene properties

In this work we present the grid of microstructures which is used for the graphene mechanical and electrical properties investigations. The design of the mask used for the grid production was presented. Afterwards the technological process steps for the grid production were described. In result the support structures – trenches – in shape of lines, squares and circles are obtained with the detail dimensions varied from 1 micrometer up to 30 micrometers. Examples of graphite and graphene deposited on the support structures are also presented.

Numerical prototyping methods in microsystem accelerometers design

The authors of this research would like to present the numerical prototyping methods in reference to design of microsystem silicon accelerometer. As an example device the capacitive accelerometer was taken into account. The accelerometer was prepared as a FEM parametric model. The model was then processed by the numerical optimization algorithms in order to find the optimal design parameters. For this purpose, the so-called numerical multi-objective optimization process was carried out. The idea was to find the optimal solution in reference to more than one optimizing criterion. As a result the set of optimal solutions was obtained and this method seems to be promising for similar purposes.