ACADEMICIAN EMIL DJAKOV INSTITUTE OF ELECTRONICS
BULGARIAN ACADEMY OF SCIENCES

72, Tzarigradsko chaussee blvd, 1784-Sofia, Bulgaria


 

LABORATORY PHYSICAL PROBLEMS OF ELECTRON BEAM TECHNOLOGIES

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RESEARCH ACTIVITIES

    

Electron beam technologies and devices are high-tech, environmental, resource-saving methods and devices, key for the development of competitive products with high quality and to achieve sustainable development based on knowledge. They are the foundation of technical progress in micro- and nano-electronics, in the production of new materials and creating new designs of instruments and precision machinery. They are becoming more widely used in the industries of the advanced industrial countries and in new research areas concerning development and optimization of applications of electron beams in nanotechnology, biotechnology, etc.

The laboratory Physical Problems of Electron Beam Technologies (PP EBT), Institute of electronics at the Bulgarian Academy of Sciences (IE-BAS) is the only one laboratory in Bulgaria and is a leading research and development unit of BAS to carry out research and development in the field of electron beam technologies (EBT) in science, industry and other areas.

The Laboratory theoretical and experimental research and development activities include: physics and characterization of intense electron beams; theoretical and experimental investigation of accelerated electron and ion penetration in materials; physical models and simulation tools for modeling of processes at sub-micron and nano-dimensional electron and ion lithography (EBL and IBL); physical processes and application of thermal electron beam treatment, electron beam melting and refining (EBMR) of metals and alloys in vacuum, electron beam welding (EBW) and surface thermal modification of materials, computer modeling and processes optimization at thermal electron beam treatment, control and automation of electron beam technologies; computer simulation of signal formation at surface and thin film analysis by electron spectroscopy.

Research activities and results of the laboratory are part of two from the fourth strategic priorities of the IE-BAS - Topic 1. Methods for development and processing of new materials and their characterization. Nanomaterials, technologies and applications. and Topic 4. Theoretical research and modeling of the interaction of electromagnetic radiation and charged particle beams with materials.

A phase analysis of intensive electron beams was developed, applicable in computer design of electron optical systems and in characterization of intensive electron beams. In the field of micro- and nano-structuring with electron and ion beam lithography, physical models and simulation tools have been developed for modeling the penetration of electrons and ions in resists and for modeling of resist development process, taking into account the peculiarities of nonlinear dissolution behavior of resists, which is important for optimization of nanostructuring technologies. Some trends in the development of electron and ion lithography of micro- and nano-structuring have been clarified. Achieved results in this area have made the laboratory a desirable partner for collaboration with German, Greek, Japanese, Slovak, Ukrainian and Chinese scientists in a number of projects, including projects funded by European sources.

At using the most powerful beams for the production of pure metals and for recycling of metal waste in vacuum, refining and heat processes are studied, and specific technologies for electron beam melting have been developed. Computer modeling of EBMR processes has been applied. On this basis the process peculiarities are investigated and the purity of the obtained metals is optimized, metals with very high purity have been obtained. Achievements in this area also enable the laboratory to collaborate with research centers and companies from the country and abroad (C-MET, India; Starck, USA; IPPC Ltd.; Targets Ltd., COMETECH Ltd., etc.).

A new physical model of EBW is proposed, based on the idea of self-focusing and the dispersion of the intense electron beam in the vapor of the treated material. Statistical analysis of experimental data from welded structures is used for development of models predicting the results of the welding process, optimization of the technology and improvement of the quality of the obtained details, automation of electron beam welding. Successful cooperation in this field with the National Polytechnic Research University, Perm, Russia.

As a result of long-term scientific cooperation with Japanese scientists, a model for computer simulation of the signal formation at surface and thin film analysis by electron spectroscopy was developed. A Bulgarian-Japanese Center for Modification of Materials with electron and ion beams was established with the Hiroshima Institute of Technology.

Members of the team have been awarded numerous national and academic awards in Bulgaria and abroad for contributions in the field of physical electronics, nanotechnology and nanoelectronics, technical progress, mathematics, learning process, etc. They have delivered lectures and reports in academic institutions and companies in Japan, Germany, India, the United States, Romania, Russia, etc. Teams of the Lab are conducting collaborative research with scientists from many countries.

The Laboratory "PP EBT" works and has successfully implemented international projects funded by the European Union and NATO, bilateral agreements and collaborations with research organizations from Germany, Japan, Russia, Slovakia, India, China, Poland, Ukraine, projects funded by the Bulgarian National Scientific Fund, ministries, departments, companies from USA, Canada, Bulgaria, contracts funded by the National Innovation Fund to the Executive Agency for Promotion of Small and Medium-Sized Enterprises by the Minister of Economy and Energy.

More important ongoing contracts and collaborations: two projects funded by the Bulgarian National Scientific Fund, one project under the Program for supporting young scientists and PhD students in BAS, a project with the Institute of Informatics of the Slovak Academy of Sciences funded by the Bulgarian National Scientific Fund, collaborations with the Hiroshima Institute of Technology, Japan, with the National Technical University of Ukraine "Kiev Polytechnic Institute", with the National Institute of Laser, Plasma and Radiation Physics of the Romanian Academy, with companies.

The research results of the team have been published in more than 350 publications, a significant part of them in prestigious international scientific journals (such as Journal Vacuum Science and Technology B - Microelectronics and Nanometer Structures, Microelectronic Engineering, Plasma Processes and Polymers, Physica C, Surface and Interface Analysis, Thin Solid Films, Vacuum, Superconductor Science and Technology, Materials, Journal of Materials Processing Technology, Modelling and Simulation in Materials Science and Engineering, Applied Mathematical Modelling, Metals, etc.), in several monographs and chapters of books in Bulgaria and abroad (Fig.1), more than 20 copyright certificates and patents (including received abroad), results have been also reported in many international forums.

Books

Fig.1.

Researchers from the laboratory have participated and actively participate in the teaching students in the University of Chemical Technology and Metallurgy, Technical University of Sofia, Sofia University "St. Kliment Ohridski", the National Research Polytechnic University in Perm, Russia, etc. and supervised and consulted many successfully defended graduates, students.

Members of the team participate in Programming and Organizing Committees of prestigious international conferences, have active expertise as reviewers in specialized international journals (such as Journal of Applied Physics, Microelectronic Engineering, Journal of Vacuum Science and Technology, International Journal of Heat and Mass Transfer, Surface Science, Materials Science, Vacuum, etc.), participate in expert and specialized councils, editorial boards, etc.

An expression of a good assessment of the active participation in international cooperation and of the research results achieved by the Laboratory "PP EBT" is accepted by the international community - IE-BAS to be the organizer of the periodically held (since 1985) international conferences on electron beam technologies.

Electron beam equipment: electron beam welding and surface heat treatment installations, equipment for electron beam melting and refining of metals and alloys.

    

    

    

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