TY - JOUR TI - Ion beam analysis of novel materials and devices involving silicon carbide and bismuth selenide DO - https://doi.org/doi:10.7282/T3F47R5H PY - 2015 AB - The properties of single crystals, thin films and their surfaces and interfaces have a critical impact on the electrical performance of devices. Analysis of the crystallinity of single crystals, the composition of thin films, surface and interface defects greatly assist the improvement of devices. Ion beams is a unique probe that provides quantitative measures of those properties. In this dissertation, ion beam techniques including Medium Energy Ion Scattering (MEIS), Rutherford Backscattering Spectrometry (RBS), Nuclear Reaction Analysis (NRA) and Helium Ion Microscopy (HIM) are used to analyze silicon carbide and bismuth selenide based structures. The 4H polytype of silicon carbide (SiC) is a promising candidate for high temperature and high power metal-oxide-semiconductor device applications due to its wide bandgap. In such applications high quality surfaces and interfaces are critical. Aspects of surface quality can be determined by backscattering spectrometry with ion channeling, where the channeling energy loss spectrum depicts the surface peaks of the crystal. We find that the SiC surface peaks are in good agreement with theoretical predictions, when including correlations of the thermal vibrations of the atoms. Hydrogen passivation of interface defects by annealing in H2 is a well-established process in silicon technology. Unfortunately this process is not effective in silicon carbide based structures. Another way of inducing hydrogen at the interface is through water vapor exposure. Nuclear Reaction Analysis (NRA) is used to measure the deuterium content in the SiC/SiO2 system induced by heavy water (D2O) anneal. Deuterium uptake in Si/SiO2, SiC(0001)/SiO2, SiC(000-1)/SiO2 and SiC(11-20)/SiO2 are being compared and the amount of deuterium at the interface is correlated with the electrical properties. The structure and chemical compatibility of In2Se3 (a band insulator) and Bi2Se3 (a 3D topological insulator) suggests possible promising applications of In2 Se3/Bi2Se3 devices. Indiffusion of indium into Bi2Se3 will affect the transport properties. We have grown In2Se3/Bi2Se3 thin films on sapphire by Molecular Beam Epitaxy at different temperatures and correlated the indium diffusion with growth temperature and mobility. KW - Physics and Astronomy KW - Silicon carbide KW - Thin films LA - eng ER -