| This thesis describes a study of heteroepitaxial thin films of {dollar}beta{dollar}-SiC grown on (001) Si by chemical vapor deposition (CVD). Electronic applications of these films have been restricted by the presence of a high density of defects. In order to prevent the formation of these defects, it is necessary to understand how they arise. The objectives of this work were to study the defect microstructure and growth mechanisms experimentally and provide explanations for these observations.; Two types of sample were investigated; continuous films and initial growth islands. Continuous films were characterised to determine the effects of substrate orientation, deposition sequence, and deposit thickness. Initial growth samples were produced by varying the temperature and duration of simulate "buffer" layer formation. The main experimental techniques used were transmission electron microscopy (TEM) and Nomarski differential interference contrast (DIC) microscopy.; The growth of SiC on (001) Si by CVD was shown to be of the Volmer-Weber growth mode. The deposits are single crystal {dollar}beta{dollar}-SiC with a parallel epitaxial relationship with respect to the substrate. The interface is semicoherent with arrays of edge-type misfit dislocations accommodating the lattice mismatch. The predominant defects in the films are stacking faults. Other types of defect present include microtwins, threading dislocations, and inversion domain boundaries (IDB's). Stacking faults and microtwins are concluded to be due to incorrect deposition on the {dollar}{lcub}111{rcub}{dollar} facets of island nuclei. The introduction of threading dislocations is attributed to residual coherency stresses. Inversion domain boundaries (IDB's) arise from the coalescence of nuclei formed on terraces separated by demi-steps. In addition, defects have been observed in the substrates; these include facetted voids and, in some cases, helical dislocations. The former result from agglomeration of vacancies, the latter are pre-existing dislocations which are pinned and climb into a helical configuration. Both of these arise during "buffer" layer formation. |
