Miscut dependent surface evolution in the process of N-polar GaN$(000\bar 1)$ growth under N-rich condition

Abstract

The evolution of surface morphology during the growth of N-polar (000 1) GaN under Nrich condition is studied by kinetic Monte Carlo (kMC) simulations for two substrates miscuts 2 o and 4 o . The results are compared with experimentally observed surface morphologies of (000 1) GaN layers grown by plasma-assisted molecular beam epitaxy. The proposed kMC two-component model of GaN(000 1) surface where both types of atoms: nitrogen and gallium attach the surface and diffuse independently, explains that at relatively high rates of the step flow (miscut angle <2 o ) the low diffusion of gallium adatoms causes surface instabilities and leads to experimentally observed roughening while for low rates of the step flow (miscut 4 o ),