Ehrlich–Schwoebel (ES) Barrier Limited Growth Morphology of Scandium Nitride

Subjected to the varied substrate temperature, thin film of III-V nitride semiconductor ScN exhibits different growth modes which affects the electronic properties significantly. Since the practical application of ScN based devices requires precise control over the electronic properties, a detailed understanding about the relation between substrate temperature and growth mode is most needed. Here, experimentally we have established that, the growth mode is determined by the competing force of temperature dependent adatom mobility and ES diffusion barrier. At low substrate temperature, the mobility of the adatoms is insufficient to cross the ES diffusion barrier which results in films having triangular grains with defects, and voids running along the edges of the triangles. When the substrate temperature is raised above some critical value, the adatoms possess sufficient energy to cross the ES barrier, which results in planar, epitaxial film growth with minute defect concentrations. This understanding of different growth modes of ScN will help to develop epitaxial defect-free single-crystalline ScN for various device applications.