The objective of the study is to provide PhD education to MSc graduates in all partial fields and to create a cross-disciplinary overview of the present development, to develop theoretical foundations in the selected research area, to master the methods of scientific, to develop their creative abilities and to use them for the solution of research problems. This all should lead to a dissertation thesis, which will provide an original a significant contribution to the research status in the field of interest.

Graduates of this program will acquire cross-disciplinary knowledge of and experience in technical and physical subjects on a high-quality theoretical level. Graduates are for their later independent research and development work equipped with the knowledge and experience from, in particular, physics of semiconductors, quantum electronics and mathematical modeling and will be able to independently solve problems associated with nanotechnologies. Potential job careers: research worker in basic or applied research and in the introduction, implementation and application of new prospective and economically beneficial procedures and processes in the field of electronics, electrical engineering, non-destructive testing and reliability and material analysis.

Graduates of this program will acquire cross-disciplinary knowledge of and experience in technical and physical subjects on a high-quality theoretical level. Graduates are for their later independent research and development work equipped with the knowledge and experience from, in particular, physics of semiconductors, quantum electronics and mathematical modeling and will be able to independently solve problems associated with nanotechnologies. Potential job careers: research worker in basic or applied research and in the introduction, implementation and application of new prospective and economically beneficial procedures and processes in the field of electronics, electrical engineering, non-destructive testing and reliability and material analysis

prof. RNDr. Pavel Tománek, CSc.

1. Dielectric materials with high permittivity

   Materials exhibiting high permittivity (dielectric constant, k) are needed for new applications, particularly in integrated circuits (ICs) using the 32 nm technology and in capacitors. In capacitors, high-k dielectrics are used in order to attain higher energy densities in capacitors and thus to reduce the size of capacitors themselves. In ICs manufacturing, the present drive toward smaller dimensions results in the thinning of insulating layers, accompanied by an unwanted increase of leakage currents. In order to prevent this effect, higher gate thicknesses are desired which, however, because of the necessity to keep the capacitance constant, should exhibit higher dielectric constant than the pure SiO2. Materials for ICs should be used within the current silicon technologies and, therefore, they must be able to sustain all manufacturing steps without being damaged. Suitable dielectrics are mostly noble metal oxides, e.g. ZrO_2, HfO_2, Al_2O_3, Y_2O_3, La_2O_3, Ta_2O_5 etc. Moreover, all materials considered must be thermodynamically stable on silicon for a long time. In case of dielectrics for capacitors, the use of multilayer ceramic chip capacitors again necessitates the use of material that can withstand sintering temperatures. The work on this topic will require experimental work in sample preparation and design, studies of the theory of high -k dielectrics and the measurement of electrical properties of developed material systems. What is available: measurement equipment for the frequency range 10-3 - 109 Hz and the helium cryostat for the temperature range 10 - 500 K.

   Tutor: Liedermann Karel, doc. Ing., CSc.

2. Dielectric properties of insulating vegetable oils for electrical engineering

   The present level of environmental protection as well as current efforts to replace crude oil products by agricultural products exert a strong pressure upon insulating oils used in electrical engineering. The main requirement is improved biodegradability while preserving the standard properties as high breakdown strength, high resistivity, low permittivity, long-term stability as well as low price. These requirements can be met by vegetable oils (e.g. line-seed or rapeseed oils), mostly methyl-esters or ethyl-esters, sometimes also triglycerides or their synthetically manufactured relatives. In some cases, a suitable substitute may also be motor and industrial oils. The subject of the study will be dielectric properties of vegetable oils intended for the use in power engineering. Studies should be focused to the impact of a particular chemical structure onto their electrical properties and to their applicability at low temperatures. The work on this topic will require experimental work in sample preparation and design and theoretical studies and measurement of electrical properties of analyzed material systems. What is available: measurement equipment for the frequency range 10-3 - 109 Hz and the helium cryostat for the temperature range 10 - 500 K.

   Tutor: Liedermann Karel, doc. Ing., CSc.

3. Investigation of electrical properties of nanocomposites

   The subject of the research will be electrical properties of nanocomposites for electrical insulation. Nanocomposites materials are based on epoxy resins containing finely dispersed both microfiller and nanofiller particles of SiO_2 and TiO_2. The presence of nanoparticles with dimensions of some 10 - 20 nm favourably affects the withstand capability of nanocomposites to partial discharges and electrical treeing and, hence, the breakdown strength as well as the degradation resistance. This in turn brings the possibility to manufacture electrical equipment (e.g. switchgear, vacuum interrupters) with smaller dimensions and weight and improved reliability. The work on this topic will include experimental work in sample preparation and design, studies of the relation between microphysical structure and electrical properties and the measurement of electrical properties of developed material systems. What is available: measurement equipment for the frequency range 1E-3 - 1E9 Hz and the helium cryostat for the temperature range 10 - 500 K, as well as established software for measurement control.

   Tutor: Liedermann Karel, doc. Ing., CSc.

4. RTS noise in MOSFETs

   The aim of this project is to determine parameters of traps in insulation layer of submicron MOSFETs by analysis of its noise characteristics, mainly RTS (random telegraph signal) noise. Experimental work is based on measurement of temperature dependence of noise using helium cryostat and study of amplitude and mean time of capture and emission as a function of electric field intensity and charge carrier concentration in channel. These results will be used to improve generation-recombination model of noise origin and localization of traps.

   Tutor: Pavelka Jan, doc. Mgr., CSc. Ph.D.

5. Study of dielectric and insulating materials with low permittivity

   Decreasing the dimensions in integrated circuits (currently 32 nm) brings about an increase of interconnect capacitance and thus the reduction of the signal propagation speed. The limiting factor for a further improvement of electronic device performance thus become not the properties of semiconductor devices themselves but rather interconnect delays and, hence, too high magnitudes of parasitic capacitances. One of the options for the reduction of interconnect capacitances is the reduction of the permittivity (dielectric constant, k) of thin-layer insulating layers (capacitance is directly proportional to permitivity). Two major routes are available: replacement of polar Si-O bonds with less polar Si-F or Si-C bonds or raising the porosity (intentional introduction of air voids). The newly developed low-k materials must, however, not limit the currently used silicon technologies and must be able to pass all manufacturing steps (temperatures up to about 1100°C). The work on this topic will require experimental work in sample preparation and design, studies of the theory of low-k dielectrics and the measurement of electrical properties of developed material systems. What is available: measurement equipment for the frequency range 10-3 - 109 Hz and the helium cryostat for the temperature range 10 - 500 K.

   Tutor: Liedermann Karel, doc. Ing., CSc.