Formation of semipolar III-nitride layers on patterned Si(100) substrates with a self-forming nanomask

The epitaxial growth of AlN and GaN layers was studied by metalorganic vapor phase epitaxy, on a Si(100) substrate, on the surface of which a V-shaped nanostructure with sub-100 nm element size (NP-Si(100)) was formed. It is shown that a corrugated surface is formed from semipolar AlN(10$\bar1$1) planes with opposite $\mathbf{c}$ axes during the formation of a semipolar AlN layer at the initial stage of epitaxy. Then, during the growth of the GaN layer, the transition from the symmetric state of two semipolar AlN planes to an asymmetric state with a single orientation of the $\mathbf{c}$ axis of the semipolar GaN(10$\bar1$1) layer occurs, and the $\mathbf{c}$ direction in the growing semipolar layer coincides with the direction of the flow of N$_2^+$ ions to the silicon surface during the formation of a nanomask.