Thin film structures own significantly different properties than the bulk material and consequently they found applications in various fields of modern nanotechnology. In the past few decades, special attention was paid to research in the field of ion beams modification of thin films. Among the techniques ion implantation is particularly emphasized, as a method that allows the incorporation of impurity atoms in the material with the possibility of precise control of process parameters. As non-equilibrium technique (not controlled by diffusion laws), ion implantation enables production of a new materials, that can not be produced with other conventional methods. The main objective of this research was to gain new fundamental knowledge in the field of modification of thin film/Si systems induced by ion irradiation. The present work consists of two parts. In the first part of the experiment the changes induced by ion implantation inside of the thin layer were examined – effects of different ionic species on the microstructure, optical and electrical properties of chromium nitride (CrN) were investigated. The second part of the experiment refers to the examination of changes at the thin film/substrate interface due to ion implantation – the influence of ion bombardment on the ion beam mixing of Co/Si system was investigated as well as formation of cobalt-silicides during the process of ion irradiation and./.or annealing of the samples. Rutherford backscattering spectrometry (RBS) was used to obtain concentration depth profiles of elements and to determine the stoichiometry of the layers. Structural and phase analyses of the systems were performed by X-ray diffraction (XRD), transmission electron microscopy combined with selected area diffraction (TEM/ SAD) and high-resolution electron microscopy analysis together with fast Fourier transformations (HRTEM/FFT). Optical properties of modified CrN layers were determined using infrared spectroscopy (IR) and electrical resistivity was measured using four point probe method. CrN thin films (thickness of ~280 nm) were deposited by reactive sputtering on crystalline silicon substrates and then implanted with 200 keV Ar+ and 80 keV V+ ions. In the case of Ar+ ions the samples were implanted in the range of 5×1015–20×1015 ions/cm2, while V+ ions were implanted to the fluence of 1×1017 and 2×1017 ions/cm2. The energies were chosen in such a way that all ions are stopped inside the layer, to avoid any atomic mixing and possible reactions at the thin film./.substrate interface. It turned out that different ionic species produces different effects in the layer, which is manifested in both the microstructural changes, as well as changes in optical and electrical properties of this material. After irradiation with Ar+ ions there are no significant changes in the composition of the layer. However, the changes were observed in the microstructure of the samples. In the implantation region the initial columnar structure of the layer firstly becomes broken and with increasing of ion fluence completely destroyed. The accumulation of defects within this area produces damage and the internal stresses in the layer, which affects the size of crystalline grains and the values of the CrN lattice constant. In contrast to the implantation of inert argon which produces only ion irradiation induced damage, the presence of vanadium, as the second transition metal, leads to the generation of chemical effects in the layer. It was observed that in the region of the layer with the highest concentration of implanted vanadium Cr0,9375 V0,0625N compound was formed. Due to the formation of a new metallic phase, as deposited CrN layer with metal/semiconductor properties shows a purely metallic character after V+ implantation. Co(50nm)/Si bilayers were prepared in high vacuum conditions, using ion beam assisted deposition technique. Two types of silicon substrates were used: crystalline (100) wafers and Si wafers pre-amorphized by low-energy Ar+ ion bombardment. After deposition the layers were implanted with 400 keV Xe+ ions to the fluence of 2×1015, 4×1015, 6×1015, 8×1015, 10×1015, 15×1015, 20×1015 and 30×1015 ions/cm2. The energy was chosen so that the effects of ion implantation are most pronounced at the thin film (Co)./.substrate (Si) interface. Then, as deposited and selected implanted samples (20×1015 Xe/cm2) were annealed for 2.h in the vacuum furnace at 200, 300, 400, 500, 600 and 700ºC. The values of atomic mixing rates showed that the structure of the substrate has a strong influence on the process of atomic transport induced by ion bombardment. Namely, in the case of pre-amorphized substrate the mixing rate of Co and Si atoms at the Co/Si interface is almost for an order of magnitude lower in comparation with crystalline Si. It is assumed that this is the result of the formation of large amount of defects, created near the surface of Si substrate during the Ar+ ions bombardment, which presents a barrier for movement of atoms from one to the other side of the interface. Low mobility of these defects prevents also the thermally activated diffusion, so even at the highest annealing temperature the formation of silicides was not observed. For the irradiated samples, independently on whether it is crystalline or pre-amorphized substrate, it is observed similar behavior: up to annealing temperatures of 400ºC poorly pronounced diffusion comes from the effects induced by ion irradiation, and at temperatures of 500–700ºC thermal mixing becomes dominant process and conditions for the compound formation were fulfilled. At the temperature of 500ºC dominant phase is CoSi, and at temperatures ≥600ºC a pure phase CoSi2 was formed. Zbog činjenice da posjeduju svojstva koja se znatno razlikuju od komadnog materijala, tankoslojne strukture su našle primjenu u raznim oblastima savremenih nanotehnologija. U posljednjih nekoliko decenija posebna pažnja je posvećena istraživanjima na polju modifikacije tankih slojeva korišćenjem jonskih snopova. Medu tehnikama se posebno istakla jonska implantacija, kao metoda koja omogućuje ugrađivanje atoma nečistoća u materijal u strogo kontrolisanim uslovima. Kao neravnotežna tehnika (nije kontrolisana zakonima difuzije), jonska implantacija omogućuje dobijanje novih materijala, koji se drugim postupcima ne mogu formirati. Osnovni cilj ovog istraživanja je sticanje novih fundamentalnih znanja u oblasti modifikacije sistema tanak sloj/Si primjenom jonskog zračenja. Predstavljeni rad se sastoji iz dva dijela. U prvom dijelu eksperimenta su posmatrane promjene koje jonska implantacija indukuje unutar tankog sloja – ispitivan je efekat različitih jonskih vrsta na mikrostrukturu, optička i električna svojstva hrom-nitrida (CrN). Drugi dio eksperimenta se odnosi na ispitivanje promjena koje uslijed jonske implantacije nastaju na granici tanak sloj/podloga – proučavan je uticaj jonskog bombardovanja na proces atomskog transporta kod Co/Si sistema i mogućnost formiranja kobalt-silicida u toku procesa jonskog zračenja i/ili odgrijavanja uzoraka. Spektrometrija Rutherford-ovim povratnim rasijanjem (RBS) je iskorišćena za dobijanje dubinskih koncentracionih profila elemenata i određivanje stehiometrije slojeva. Za strukturnu analizu i identifikaciju prisutnih faza u uzorcima korišćena je difrakcija X-zračenja (XRD), transmisiona elektronska mikroskopija u kombinaciji sa elektronskom difrakcijom na odabranoj površini (TEM/SAD) i visoko-rezoluciona elektronska mikroskopija uz analizu pomoću Fourier-ove transformacije (HRTEM/FFT). Optička svojstva modifikovanih CrN slojeva su određena korišćenjem infracrvene spektrofotometrije (IR), a električna otpornost je mjerena metodom ”četiri tačke”. Tanki slojevi CrN (debljine ~280 nm) su deponovani metodom reaktivnog jonskog rasprašivanja na kristalnim silicijumskim pločicama, a zatim su implantirani sa 200 keV Ar+ i 80 keV V+ jonima. U slučaju Ar+ jona uzorci su implantirani u opsegu od 5×1015–20×1015 jona/cm2, dok su joni V+ implantirani do doze 1×1017 i 2×1017 jona/cm2. Energije su odabrane tako da se svi joni zaustave u sloju, da bi se izbjeglo atomsko miješanje i moguće reakcije na granici sloj/podloga. Pokazalo se da različite jonske vrste proizvode drugačije efekte u sloju, što se manifestovalo kako u mikrostrukturnim promjenama, tako i u promjenama optičkih i električnih svojstava ovog materijala. Nakon ozračivanja sa jonima Ar+ ne dolazi do značajnih promjena u sastavu sloja. Međutim, uočene su promjene u mikrostrukturi uzoraka. U zoni implantacije prvo dolazi do narušavanja, a sa povećanjem doze i do potpunog uništenja prvobitne stubičaste strukture sloja. Nakupljanje defekata unutar ove oblasti proizvodi oštećenja i unutrašnja naprezanja u sloju, što utiče na veličinu kristalnih zrna i na vrijednost konstante CrN rešetke. Za razliku od implantacije inertnog argona gdje dolazi samo do pojave jonskim zračenjem indukovanog oštećenja, prisustvo vanadijuma, kao drugog prelaznog metala, dovodi do pojave hemijskih efekata u sloju. Uočeno je da u zoni sloja sa najvećom koncentracijom implantiranog vanadijuma dolazi do formiranja Cr0,9375 V0,0625.N jedinjenja. Formiranje nove metalne faze ima za posljedicu da deponovani CrN sloj sa metalno/poluprovodničkim svojstvima, nakon V+ implantacije pokazuje izraziti metalni karakter. Dvoslojni sistemi Co(50nm)/Si su pripremljeni u uslovima visokog vakuuma, korišćenjem metode deponovanja potpomognutog jonskim snopom. Korišćene su dvije vrste silicijumskih podloga: kristalne pločice orijentacije (100) i podloge sa površinom amorfizovanom bombardovanjem sa niskoenergetskim Ar+ jonima. Nakon deponovanja slojevi su implantirani sa 400 keV Xe+ jonima do doze 2×1015, 4×1015, 6×1015, 8×1015, 10×1015, 15×1015, 20×1015 i 30×1015 jona/cm2. Energija je odabrana tako da efekti jonske implantacije budu najizraženiji na granici tanak sloj (Co)/podloga (Si). Deponovani i odabrani implantirani slojevi (20×1015 Xe/cm2) su za