Area-Selective Epitaxial Growth of GaAs on GaAs(111)A Substrates by Migration-Enhanced Epitaxy

Abstract

We have carried out area-selective epitaxial growth of GaAs on GaAs(111)A substrates using migration-enhanced epitaxy and have investigated the pyramidal hillocks formed on the grown surface. Scanning electron microscopy and atomic force microscopy observations indicate that these hillocks can be classified into two types: hillocks with small top plateaus and those with large plateaus. Investigations on the growth condition dependence of surface morphology and plan-view transmission electron microscopy observation have revealed that both types of hillocks are caused by stacking faults. Hillock cores are found to be stacking fault tetrahedra, whose formation processes result in two types of hillocks. Additionally, we have succeeded in improving the surface flatness by increasing the surface arsenic pressure during growth.

Ehrlich-Schwöbel effect on the growth dynamics of GaAs(111)A surfaces

“…In particular we have identified and analyzed the factors that lead to huge overall roughness on this surface: i) the presence of defect induced hillocks; ii) the island 3D growth. The latter has been often overlooked in previous studies, thus preventing the achievement of a truly atomically flat surface 18,19 .…”

“…It is worth noting that being the exponent p = i * /(i * + ζ), for any value of i * < ∞, we get that 5 3 p < 2, so that ω increases proportionally with the increasing of Ga flux F . The exponent q is always positive, being the effect of As flux to decrease group III adatom diffusion 18,19 B. Discussion of the results A fundamental ingredient for the discussion is the knowledge of the parameters involved in the model, namely the two exponents p and q, the activation energy E n , and the ES barrier energy E S .…”

“…The (111) surface morphology, in most of the cases, is still affected by a large surface roughness. In particular, the growth of highly flat GaAs and AlGaAs (111)A surfaces, and consequently of high quality nanostructures grown on this substrate, is strongly subordinated to the possibility of inhibiting the formation of large (with µm lateral dimensions) pyramidal hillocks with threefold symmetry, nucleated by stacking faults 18,19 .…”

InAs heteroepitaxy on nanopillar-patterned GaAs (111)A

“…Nanopillar-patterned areas of approximately 1. Formation of such hillocks with edges oriented along the < 11 ̅ 0 > directions is widely reported in literature [14,15,16] for homo-and heteroepitaxial growth on fcc (111)…”

“…Formation of such hillocks with edges oriented along the < 11 ̅ 0 > directions is widely reported in literature [14,15,16] for homo-and heteroepitaxial growth on fcc (111) surfaces. A high Ehrlich-Schwoebel barrier [17] at step edges of 2D islands restricts the downward motion of adatoms and facilitates 3D growth by increasing their residence time on a 2D terrace and thus also the probability of forming new 2D layers on top of existing ones [18,19].…”