In situ high-temperature scanning tunneling microscopy studies of early stage growth kinetics during titanium nitride epitaxy

NaCl-structure TiN is widely used as a hard wear-resistant coating on cutting tools, as a diffusion-barrier layer in microelectronic devices, as a corrosion-resistant coating on mechanical components, and as an abrasion-resistant layer on optics and architectural glass. Even though its diffusion barrier and elastic properties are known to be anisotropic, and hence depend upon grain orientation, little is known regarding the mechanisms and reaction paths leading to the development of preferred orientation in polycrystalline TiN layers deposited by reactive evaporation and sputter deposition.; Efforts to model polycrystalline growth as a function of deposition conditions is a complex problem. As a minimum set, one requires adatom transport parameters—activation barriers for surface diffusion step edge attachment/detachment, the adatom formation energy, the step edge Ehrlich barrier, and the step formation energy—all as a function of orientation. Unfortunately, very little data, either experimental or theoretical, is available concerning these parameters for TiN.; During the course of my research, I have developed methods to grow atomically-smooth TiN(001) and (111) single-crystal layers with simple well-defined single-atom-high 2D island configurations on large atomically-smooth terraces. I used in situ scanning tunneling microscopy to study time- and temperature-dependent 2D island coarsening/decay kinetics, obtain 2D equilibrium island shapes, and follow temporal fluctuations of island shapes on both TiN(001) and (111) surfaces. I have developed a combination of experimental and theoretical techniques to analyze the surface dynamics measurements and determined adatom surface transport parameters, step energies, step stiffnesses, and kink formation energies on TiN(001) and TiN(111) surfaces.