SVIBOR - Project code: 1-03-178

MINISTRY OF SCIENCE AND TECHNOLOGY

Strossmayerov trg 4, HR - 10000 ZAGREB
tel.: +385 1 459 44 44, fax: +385 1 459 44 69
E-mail: ured@znanost.hr

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Project code: 1-03-178


STUDY OF DEFECTS IN SEMICONDUCTORS


Main researcher: DESNICA, UROŠ (9386)


Assistants
Type of research: basic
Duration from: 01/01/91. to 12/31/93.
Papers on project (total): 113
Papers on project quoted in Current Contents: 57
Institution name: Institut "Ruđer Bošković", Zagreb (98)
Department/Institute: Materials Research and Electronic Department
Address: Bijenička 54
City: 10000 - Zagreb, Croatia
Communication
Phone: 385 (0)1-4561-111
Fax: 385 (0)1-425-497
E-mail: Desnica@irb.hr
Summary: "In the project "Study of defects in Semiconductors" microscopic defects (native defects, impurities, dopants, complexes...) has been studied as well as their influence on the macroscopic properties of semiconductors. Main goals of this research was the study of specific, today most interesting, defects and related fundamental physical phenomena at the atomic scale, in order to understand and get control over defects, as a vital prerequisite for optimization of properties and finally the "engineering" of these important materials. A number of specific problems has been investigated and solved successfully in different semiconductors, particularly in: Mono- and polycrystalline silicon: The properties and role of oxygen, carbon and metallic impurities, including their interactions during various treatments (thermal treatment, gamma-irradiation etc.) have been elucidated, and also of hydrogen and carbon in amorphous silicon. In gallium arsenide: defects with deep levels, which were thoroughly characterized (energy levels; cross sections etc.) It has been shown that these defects are responsible for a number of previously unresolved low-T properties (dramatic changes of photosensitivity, transient photoconductivity, persistent currents etc.). In cadmium sulfide: cadmium vacancy has been identified as the main native defect responsible for the compensation of electrical activity of donor dopants. It has been demonstrated how cadmium vacancies can be introduced or annihilated in a controlled way. Specific characteristic of this project was extensive international cooperations, which gave us an access to a number of modern research techniques, and resulted in joint publications with 17 foreign scientific institutions. Results of the five-year project were published in 73 publications in international journals, books and proceedings (please see enclosed lists). Among them, 53 papers were published in the most prominent journals, secondary refereed in "Current Contents" (CC).

Keywords: semiconductors, defects, impurities, dopants, deep levels, silicon, gallium arsenide, cadmium sulfide, Raman spectroscopy, IR spectroscopy, micro-FTIR,.

Research goals: Study of defects is an exceptionally important part of the semiconductors physics, as defects govern many of the most important macroscopic properties of these materials. Therefore, the applicability and usability of semiconductors in modern technologies (electronics, micro- and opto-electronics, informatics, telecommunications, automatization etc.) is limited by the knowledge of the basic properties of defects. The goal of proposed study was to acquire and deepen the knowledge about fundamental properties of most important defects (impurities, dopants, native defects and their complexes) in semiconductors, and to solve a number of specific, today most interesting open problems of the particular defects in Si, GaAs etc.. The goal was to investigate and understand: a) basic properties of particular defects at the atomic level, and -where possible-, to determine microscopic structure of defect and its immediate surroundings; b) determine its dynamic properties (interactions between defects and with host atoms due to thermal, optical and other excitations) and c) to determine the influence of particular defects on macroscopic properties of materials. Defects were studied in a number of semiconductors, which were selected either as being very important today or as prospective in the future. In silicon (monocrystalline, polycrystalline and amorphous) most common and most important impurities were studied (oxygen, carbon, hydrogen..). In compound semiconductors (particularly in gallium arsenide, indium phosphide and cadmium sulfide) primarily native defects and complexes were studied. Furthermore, the goal was to achieve and maintain the highest scientific standards and the quality of these investigation. We believe that all these goals were successfully fulfilled: A number of specific problems of today's most interesting defects have been either solved or an important scientific contribution has been added to their understanding. Results of these research have been published in a considerable number of papers in best international journals (please see enclosed List of publications).

COOPERATION - PROJECTS


  1. Name of project: 1-03-066 Vibracijski fenomeni i interakcije u kondenziranoj materiji
    Name of institution: Institut " Rudjer Bošković "
    City: 10000 - Zagreb, Croatia

  2. Name of project: 1-03-180 Istraživanje tankih poluvodičkih filmova
    Name of institution: Institut "Rudjer Bošković"
    City: 10000 - Zagreb, Croatia

COOPERATION - INSTITUTIONS


  1. Name of institution: Universita di Pavia
    Type of institution: Economical/Production
    City: Pavia, Italija

  2. Name of institution: MEMS Electronic Materials
    Type of institution: University/Faculty
    City: Novara, Italija

  3. Name of institution: CNR,
    Type of institution: University/Faculty
    City: Pavia, Italija

  4. Name of institution: Universita di Modena
    Type of institution: Economical/Production
    City: Modena, Italija

  5. Name of institution: Universita di Trento
    Type of institution: Economical/Production
    City: Trento, Italija

  6. Name of institution: IRST
    Type of institution: University/Faculty
    City: Trento, Italija

  7. Name of institution: Siemens Telecomunicazioni
    Type of institution: State institute
    City: Milano, Italija

  8. Name of institution: Instituto MASCPEC_CNR
    Type of institution: University/Faculty
    City: Parma, Italija

  9. Name of institution: Universite Louis Pasteur
    Type of institution: Economical/Production
    City: Strasbourg, Francuska

  10. Name of institution: Universitat Konstanz
    Type of institution: Economical/Production
    City: Konstanz, Njemačka

  11. Name of institution: Fraunhofer Institut
    Type of institution: University/Faculty
    City: Freiburg, Njemačka

  12. Name of institution: Mobil Solar Energy Corp.
    Type of institution: University/Faculty
    City: Boston, USA

  13. Name of institution: Oak Ridge National Laboratory
    Type of institution: University/Faculty
    City: Oak Ridge, USA

  14. Name of institution: Cabot Corp.
    Type of institution: University/Faculty
    City: Billerica, MA, USA

  15. Name of institution: University of Albany
    Type of institution: Economical/Production
    City: Albany, USA

  16. Name of institution: ICTP
    Type of institution: University/Faculty
    City: Trst, Italija

  17. Name of institution: CNRS
    Type of institution: University/Faculty
    City: Strasbourg, Francuska

  18. Name of institution: niversite Montpellier II
    Type of institution: Economical/Production
    City: Montpellier, Francuska
Other information about the project.
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