Step bunching process induced by the flow of steps at the sublimated crystal surface

Abstract

Stepped GaN(0001) surface is studied by the kinetic Monte Carlo method and compared with the model based on Burton-Carbera-Frank equations. Successive stages of surface pattern evolution during high temperature sublimation process are discussed. At low sublimation rates clear, well defined step bunches form. The process happens in the absence or for very low Schwoebel barriers at the ideal surface. Bunches of several steps are well separated, move slowly and are rather stiff. Character of the process changes for more rapid sublimation process where double step formations become dominant and together with meanders and local bunches assemble into the less ordered surface pattern. Solution of the analytic equations written for one dimensional system confirms that step bunching is induced by the particle advection caused by step-flow anisotropy. This anisotropy becomes important when due to the low Schwoebel barrier both sides of step are symmetric. Simulations show that in the opposite limit of very high Schwoebel barrier steps fracture and rough surface builds up.

Step bunching and macrostep formation in 1D atomistic scale model of unstable vicinal crystal growth

“…The most often discussed in this context are biased adatom diffusion i.e. due to electromigration [10,14] or the existence of Ehrlich-Schwoebel barrier (SB) [1,[3][4][5]15]. Below we will concentrate on these two sources of the surface instability.…”

“…For this it is necessary to reach a fundamental understanding of the growth mechanisms and their consequences on atomic scale. This is why surface morphologies resulting from various kinds of crystal growth processes are subject of interest for large groups of researcher [1][2][3][4][5]. Surface self-organization resulting in well-ordered structures is used to build templates for growing nano-scale objects such as nano-dots or nano-wires [6,7].…”

Simulation of the Growth Kinetics in Group IV Compound Semiconductors

“…[10,14]), or they simulate Si and C individually but the defect formation and evolution cannot be estimated (see Refs. [15,16]). In this paper we present a method satisfying both these requirements.…”

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

“…We use the model that is based on the one previously implemented to study growth and sublimation of GaN(0001) surface. [11][12][13][14] The model is developed in such a way that both types of atoms building crystal: nitrogen and gallium are controlled. They attach to the surface, diffuse and detach independently.…”