TY - JOUR

T1 - Structural and morphological instabilities of the Si(1 1 1)-7 × 7 surface during silicon growth and etching by oxygen and selenium

AU - Rogilo, Dmitry

AU - Sitnikov, Sergey

AU - Ponomarev, Sergey

AU - Sheglov, Dmitry

AU - Fedina, Liudmila

AU - Latyshev, Alexander

N1 - Funding Information: This research was performed on the equipment of CKP “Nanostruktury”. Experiments on Si growth were financially supported by Russian Science Foundation [grant number 19-72-30023 ], experiments on Si etching by selenium were financially supported by Russian Science Foundation [grant number 18-72-10063 ], experiments on Si etching by oxygen were financially supported by State Government Task. Publisher Copyright: © 2020 Elsevier B.V. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2021/2/28

Y1 - 2021/2/28

N2 - Using in situ reflection electron microscopy and ex situ atomic force microscopy, we have studied the morphological stability of large-scale (~10–100 μm) Si(1 1 1)-7 × 7 terraces during silicon growth and etching by oxygen and selenium. On the large-scale terraces, silicon growth at substrate temperatures T = 600–770 °C and Si deposition rates R = 0.002–0.2 BL/s proceeds in multilayer mode. Based on RMS surface roughness scaling W ∝ Θβ, we have discerned three modes of morphological instability caused by (I) effective adatom diffusion along step edges at low T and R (β ≈ 0.33), (II) effective diffusion and fast step motion along disordered “1 × 1” regions in 7 × 7 domain boundaries at intermediate T and R (β ≈ 0.2), and (III) accumulation of Si adatoms in high-atom-density “1 × 1” regions on the uppermost terraces at high T and R (β ≈ 0.5). The etching of the singular Si(1 1 1)-7 × 7 surface by oxygen leads to the slow development of multilayer morphology, while selenium-induced etching preserves flat surface morphology with periodic 2D vacancy island nucleation, growth, and coalesce, which is attributed to Se adatom diffusion. On the step-bunched surface, the Si or Se adatom diffusion to the step bunches leads to the self-organization of pyramidlike or valley-like morphology during Si growth or Se-induced etching, respectively.

AB - Using in situ reflection electron microscopy and ex situ atomic force microscopy, we have studied the morphological stability of large-scale (~10–100 μm) Si(1 1 1)-7 × 7 terraces during silicon growth and etching by oxygen and selenium. On the large-scale terraces, silicon growth at substrate temperatures T = 600–770 °C and Si deposition rates R = 0.002–0.2 BL/s proceeds in multilayer mode. Based on RMS surface roughness scaling W ∝ Θβ, we have discerned three modes of morphological instability caused by (I) effective adatom diffusion along step edges at low T and R (β ≈ 0.33), (II) effective diffusion and fast step motion along disordered “1 × 1” regions in 7 × 7 domain boundaries at intermediate T and R (β ≈ 0.2), and (III) accumulation of Si adatoms in high-atom-density “1 × 1” regions on the uppermost terraces at high T and R (β ≈ 0.5). The etching of the singular Si(1 1 1)-7 × 7 surface by oxygen leads to the slow development of multilayer morphology, while selenium-induced etching preserves flat surface morphology with periodic 2D vacancy island nucleation, growth, and coalesce, which is attributed to Se adatom diffusion. On the step-bunched surface, the Si or Se adatom diffusion to the step bunches leads to the self-organization of pyramidlike or valley-like morphology during Si growth or Se-induced etching, respectively.

KW - A1. Etching

KW - A1. Morphological stability

KW - A1. Surface processes

KW - A3. Molecular beam epitaxy

KW - B2. Semiconducting silicon

KW - OXIDATION

KW - Morphological stability

KW - Etching

KW - MOUND FORMATION

KW - EPITAXY

KW - PHASE

KW - SI

KW - ISLAND NUCLEATION

KW - Molecular beam epitaxy

KW - Semiconducting silicon

KW - SCANNING-TUNNELING-MICROSCOPY

KW - DIFFUSION

KW - Surface processes

KW - STEP PERMEABILITY

KW - ELECTRON-MICROSCOPE

UR - http://www.scopus.com/inward/record.url?scp=85096182383&partnerID=8YFLogxK

U2 - 10.1016/j.apsusc.2020.148269

DO - 10.1016/j.apsusc.2020.148269

M3 - Article

AN - SCOPUS:85096182383

VL - 540

JO - Applied Surface Science

JF - Applied Surface Science

SN - 0169-4332

M1 - 148269

ER -