Multimodal imaging technology by integrated scanning electron, force, and microwave microscopy

Significance 

The most common practice for performing accurate analysis of surface topography involves the utilization of both scanning electron microscopy and scanning probe microscopy. A combination of the two modalities has been observed to have abundant advantages, such as localization, navigation etc. The past two decades has seen various approaches purposed to integrate atomic force microscopes into scanning electron microscopes for application in nano-electronic transport processes and cathode-luminescence based studies. Furthermore, the combination of a scanning tunnel microscope with a microwave resonator has borne the scanning microwave microscope which has found numerous applications. Unfortunately, using this technique to extract information of the complex quantities of conductivity, permittivity, and permeability has been a challenge. Therefore, it is imperative to comprehend both the interaction of the incident electromagnetic wave and the physics of the sample so as to obtain the quantitative data from the measurements.

To this note, University of Oldenburg researchers at the Department for Computing Science: Dr. Olaf C. Haenssler and Professor Sergej Fatikow in collaboration with Professor Didier Theron, of CNRS-IEMN in Lille, France employed the integrated scanning microwave microscope technique to simultaneously extract multimodal nanoscale specimen information. The combination of multiple imaging techniques allowed them to obtain complementary and unique datasets of the samples under investigation. Their work is currently published in Journal of Vacuum Science & Technology B.

Briefly, the research method employed involved the use of an atomic force microscope based on a compact optical interferometer to perform imaging of surface topographies and a scanning microwave microscope to record electromagnetic properties in the microwave frequency domain up to 20 GHz at the same time and spot. In addition, an open-source software framework, which was tailored for vision-based automation by nanorobotics, was used to control the instrument.

The authors observed that the capacitance approximation formulas for rectangular metal-oxide-semiconductor structures in literature deviated from the RF simulation results obtained by more than 20%. Moreover, the capacitance values in the considered area of 380 aF, showed strong contrast thereby proofing the concept. However, it was noted that smaller scaled features were not available at the time of preparation.

In summary the University of Oldenburg and CNRS-IEMN scientists successfully presented a hybrid technology developed by integrating several microscopy modalities which enabled them extract multiple information of sample surfaces by detection of electron, light, microwave interaction and atomic force. In general, a study of micro-scaled capacitors was undertaken so as to evaluate the developed instrumental platform and show the potential of the resulting multimodal technology. Altogether, their setup demonstrated here allows for simultaneously observation of the region-of-interest with scanning electron microscopy resolution, while imaging and characterization with evanescent microwaves and atomic forces.

Multimodal imaging technology by integrated scanning electron, force, and microwave microscopy - Advanced Engineering

About the author

Olaf C. Haenssler studied electrical engineering at the University of Applied Sciences Emden, Germany, and received his engineer diploma in 1989 with work on RF electromagnetic field measurements. After many years working in different R&D fields of physics and electronics in industry and academia, like marine remote sensing, communications- and satellite technology, he is a research associate at the Division of Microrobotics and Control Engineering (AMiR) at the University of Oldenburg since 2001. He has been also a member of the Nano And MicroSYStems (NAM6) Group at Institute of Electronics, Microelectronics and Nanotechnology (IEMN), Villeneuve d’Ascq, France, between 2013 and 2017. In 2018 he received his doctoral degree in computer science from the University of Oldenburg, Germany and his Ph.D. in micro- , nanoelectronics and microwaves from University of Lille, France.

He founded the group Microwave Nanoscopy and Automation at Nanoscale at Oldenburg University. His research focuses on the microwave microscopy and measurements in combination with nanorobotics.

He was elected as Senior Member of IEEE and is reviewer of Applied Physics Letters, IEEE Transactions on Instrumentation & Measurement, IEEE Robotics and Automation Letters and of the Austrian Research Promotion Agency.

About the author

Didier Théron was trained at the “Ecole Polytechnique” in Palaiseau, France where he received the engineer diploma in 1984. After a master degree in Solid State Physics at the University of Paris-Sud, Orsay, France in 1985, he got his PhD in physics at the Swiss Federal Institute of Technology in Lausanne, Switzerland in 1989 on the physical simulation and MBE growth of GaAs based multichannel HEMTs. Since 1990, he is researcher (CNRS) and works at Institute of Electronics, Microelectronics and Nanotechnology (IEMN, Villeneuve d’Ascq, France).

He first investigated the physics and technology of GaAs and InP based power HEMTs for millimeter wave applications (from 10 to 94 GHz). Then he worked on GaN HEMTs in cooperation with Alcatel/Thales III-V lab. In 1998, he defended his habilitation thesis at the University of Sciences and Technology of Lille. In 2006, he moved to the field of MEMS to apply his expertise on electron devices to inertial resonant MEMS. Since then, he investigates GaN and Si MEMS resonators for force sensors and in particular for high frequency (10 MHz) AFM probes. In 2009, in collaboration with Keysight Technologies, he developed expertise in Scanning Microwave Microscopy coupled to RF interferometry for the investigation at the nanoscale of various materials and devices such as aF-scale Au nanodot capacitances, Ferrocenealkane Thiol grafted to Au nanodots or TiO2 based memristor devices.

He has about 85 peer-reviewed papers and 85 peer-reviewed communications in conferences (13 invited) and 2 patents. In 1998, he received the CNRS Bronze medal for his work on the physics and technology of power HEMTs for millimetre wave applications.

From September 2013 to December 2015, he headed the Nano And MicroSYStems (NAM6) group of IEMN. He took also administrative responsibilities at CNRS from 2004 to 2008, at the national funding research organisation (ANR) from 2009 to 2012 and from 2013 at the ministry of research.

About the author

Prof. Sergej Fatikow studied electrical engineering and computer science at the Ufa Aviation Technical University in Russia, where he received his doctoral degree in 1988 with work on fuzzy control of complex non-linear systems. During his work in Russia he published over 30 papers and received over 50 patents in intelligent control and mechatronics. In 1990 he moved to the Institute for Process Control and Robotics at the University of Karlsruhe in Germany, where he worked as a postdoctoral scientific researcher and since 1994 as Head of the research group “Microrobotics and Micromechatronics”. He became an assistant professor in 1996 and qualified for a full faculty position by habilitation at the University of Karlsruhe in 1999. In 2000 he accepted a faculty position at the University of Kassel, Germany. A year later, he was invited to establish a new Division for Microrobotics and Control Engineering (AMiR) at the University of Oldenburg, Germany. Since 2001 he is a full professor in the Department of Computing Science and Head of AMiR.

His research interests include micro- and nanorobotics, industrial robotics and automation at nanoscale, nanohandling inside SEM, AFM-based nanohandling, sensor feedback at nanoscale, and neuro-fuzzy robot control. He is author of three books on microsystem technology, microrobotics and microassembly, robot-based nanohandling, and automation at nanoscale.

Since 1990 he published over 150 book chapters and journal papers and over 300 conference papers.

Prof. Fatikow is Founding Chair of two international conferences, MARSS and 3M-NANO, and Chair of IEEE-RAS Technical Committee on Micro/Nano Robotics and Automation.

Reference

Olaf C. Haenssler, Sergej Fatikow, Didier Theron. Multimodal imaging technology by integrated scanning electron, force, and microwave microscopy and its application to study micro-scaled capacitors. Journal of Vacuum Science & Technology B 36, 022901 (2018); doi: 10.1116/1.5006161

Go To Journal of Vacuum Science & Technology

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