| High quality substrate material was eagerly needed in the heteroepitaxial growth process of diamond. In order to obtain highly oriented or single crystal diamond film, a kind of highly oriented or single crystal substrate should be designed. In the present work, a suitable structure was designed by the simulation method. And on the other hand, experiments of different deposition parameters were put on to prepare and characterize the multi-layers.By using the method of simulation and experiment respectively, related research of the designed structure and the prepared thin films was carried on.Materials Studio was used in the simulation part as a kind of analysis calculation software for materials, in order to explain why the iridium(Ir) is helpful for diamond heteroepitaxy growth and how Ti N transition layer plays a significant role for the entire structure. The Ti N, Mg O and Ti N/Mg O films were deposited by pulsed laser deposition(PLD) method at different conditions after that. Then, step profiler,scanning electron microscopy(SEM), atomic force microscopy(AFM), X-ray photoelectron spectroscopy(XPS), grazing incidence X-ray diffraction(GIXRD)and nano-mechanical systems(nanoindentation and nano-scratch) were used to characterize morphologies, roughness, bond and binding energy, structure and mechanical properties of the films.The multi-layers structure was designed according to the design guidelines of the substrate for hetero-epitaxial. The structure which was based on Si(100) and can achieve the purpose of hetero-epitaxial was composed of Si(100)/Ti N(100)/Mg O(100)/Ir(100). The performance of Ti N and Mg O ceramics was simulated by Materials Studio, as well as the combination of Mg O film on Si O2 or Ti N layers,indicating the presence of Ti N buffer layer between the Si substrate and Mg O film plays an important role in improving the binding properties because of the formation of chemically-as Ti-N-Mg-O bond. Meanwhile, the performance of carbon atoms on Si had also be simulated, to compare with that on iridium(Ir). No adsorption,dissolution and precipitation process was observed as that in Ir, which can obviously improve nucleation density of diamond and the quality of diamond film.In the pre-experiments, the performance of poly and single crystal diamond was compared, the suitable Ti N and Mg O targets for films deposition were perpared and characterized, and the clear Si substrate was obtained by a pre-oxidation cleaning process.Quasi-single crystal Ti N films and Mg O/Ti N stacks with atomically smooth surface(surface roughness average Ra <0.3 nm) and a highly(100) oriented wereprepared in the present work. The quality of the films was improved with the increase of the laser energy, substrate temperature and pulse frequency. Namely a smoother surface, a better binding properties between particles(with binding energy increases), a more highly preferentially oriented and the improvement of mechanical properties were gained. Moreover, the introduction of Ti N transition layer(or template) plays a significant role to improve preferentially orientation and deposition quality. When Mg O thin films were prepared on Si substrate directly, the films show a structure with both the Periclase and Magnesium Oxide phases, and the introduction of appropriate thickness of the Ti N layer can make Mg O thin films with only Periclase phase.It provides a possibility for the growth of high-quality diamond film as the smooth and highly oriented stack was obtained. And it can alse be found that for the preparation of thin films by pulsed laser deposition(PLD), the use of higher laser power, the substrate temperature and the laser pulse frequency, can significantly improve the quality of the film, the film under suitable conditions for preparing,found that the laser energy and the substrate temperature has a certain compensation performance, increase the laser energy to bring additional energy particles migrate to the surface of the substrate, the substrate temperature can supplement particles triggered by the lack of accumulation. At the same time, the structure of the interface of the film and the substrate and buffer layer were analyzed in combination,the interface characteristic diffraction peaks changes with the state of film composition and deposition varies, the epitaxial film characteristics can explain to some extent. |
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