Dubikovskii O. Ion-beam modification and quantitative mass spectrometric analysis of nanoscale semiconductor structures.

Українська версія

Thesis for the degree of Doctor of Philosophy (PhD)

State registration number


Applicant for


  • 105 - Прикладна фізика та наноматеріали


Specialized Academic Board

ДФ 26.199.007

VE Lashkarev Institute of Semiconductor Physics of the National Academy of Sciences of Ukraine


Studies of the physical properties of nanoscale objects, thin semiconductor and metal films have demonstrated the unique functional properties of these materials compared to bulk ones. It is the physical phenomena at the phase boundaries, quantum-dimensional effects allow to create new generations of microelectronic devices and circuits in which the size of the active elements are tens or even units of nanometers. Research of such structures and technological solutions for their manufacture require the use of new techniques that take into account the specifics of the studied objects. Such techniques should certainly include ion-beam technology. The application of these technologies allows to form new materials, or to carry out their radical structural and phase modification, and this requires a detailed study of physical processes with the involvement of the most modern research methods. One of the most powerful methods for studying the impurity composition of substances is the mass spectrometry of secondary ions. The first section provides a brief overview of the literature on the topic of the dissertation and highlights the problems that require detailed study. The description of the time-of-flight mass spectrometry method is given, the optimal measurement parameters are determined, which allow to investigate the structures of nanometer dimensions. By the method of ion implantation of a number of impurities, test samples were made to calibrate the results of mass spectrometric studies, which allowed quantitative measurements of the concentration of impurities. The coefficients of elemental sensitivity of the method were determined and the resolution of the time-of-flight mass spectrometry method at a depth of the order of 1 nm was achieved using structures with delta-doped layers. In the second section, a numerical procedure for calculating the current-voltage characteristics was developed, which was used to analyze the InSb diode with a p-n junction and determined the optimal doping profile of InSb implanted by Be+ ions. It is shown that to ensure optimal parameters of photodiodes it is necessary to implant beryllium with different energies. Using mass spectrometry, the distribution profiles of the doping impurity were investigated and the optimal depth of the p-n junction was determined. The processes of photon annealing of implanted structures are investigated, the optimal annealing parameters are determined. It has been shown that oxides of indium and antimony are formed during annealing, and antimony segregation also occurs. Modes of additional processing which lead to reduction of such parasitic effects are found. The processes of passivation of diode structures have been studied and it has been shown that the optimal coatings are silicon nitride films doped with hydrogen. The technology was developed and experimental samples of photodiodes were made. The third section is devoted to the study of oxygen generation processes during the implantation of carbon ions. It is shown that the oxygen generated from the volume accumulates in the area of vacancy distribution and at the phase boundary of natural oxide - silicon. The optimal technological modes for the generation of thermodonor centers are determined. The optimal implantation dose and annealing temperature for efficient generation of TD centers were found. It is shown that the region of formation of TD centers depends on the energy of implantation of carbon ions. The photosensitivity of structures with a hidden n+ layer is determined by the processes of recombination of charge carriers in the near-surface defective region. In the fourth section of the dissertation, a study of two-layer Pt / Fe structures obtained by magnetron sputtering was performed. The evolution of their structure and magnetic properties after annealing and ion doping was studied by XRD and SIMS methods. It has been shown that the implantation of N+ ions can reduce both the temperature and the annealing time required to promote diffusion-structural phase transitions. It is concluded that the use of ion doping is a promising way to create a self-organizing method of heterostructure forming. The fifth section of the dissertation contains the results of studies of multilayer structures Co/Si, Mo/Si and AlN/GaN after their modification by ion implantation of impurities. A new effect is found, which consists in increasing the nominal thickness of the existence of the amorphous-cluster state of cobalt films and delaying the subsequent explosive crystallization of the growing cobalt film due to doping with carbon atoms. It is shown that the accumulation of oxygen at the Mo/Si interfaces is one of the main causes of degradation of the multilayer structure during overheating. 3D-measurements of ToF-SIMS revealed the penetration of silicon into molybdenum.


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