Equivalent Step Structures along Inequivalent Crystallographic Directions on Halogen-Terminated Si(111)-(1×1)Surfaces

Abstract

Steps in inequivalent crystallographic directions are usually assumed to have different atomic structures. However, this Letter demonstrates that bilayer steps in the two principal crystallographic directions (͗ 1 12͘ and ͗112 ͘) of the Br-terminated Si(111)-͑1 3 1͒ surface have the same atomic edge structure, due to the introduction of stacking faults along the ͗112 ͘ step edges. Similar results are also observed for Cl-and I-terminated Si (111) surfaces. This strong preference for a particular step edge structure determines the surface morphology of steps, islands, and etch pits, and has profound ramifications for dry etching and chemical vapor deposition growth for this system. [S0031-9007(96)02002-9]

An STM and LEED study of MOCVD-prepared P/Ge (1 0 0) to (1 1 1) surfaces

“…Stacking faults dramatically alter the bonding geometry at domain boundaries, and sometimes this is energetically favorable [22]. This can be illustrated using the (8 7 7) primitive unit cell shown in the STM image of Fig.…”

Atomic structure of chlorinated Si(113) surfaces

“…31 An atomic model of this so-called A-type step-edge geometry has already been proposed based on STM investigations for Br/Si͑111͒ ͑Ref. 31͒ and H/Si͑111͒.…”

Chlorination−Methylation of the Hydrogen-Terminated Silicon(111) Surface Can Induce a Stacking Fault in the Presence of Etch Pits

“…To test this possibility, periodic DFT calculations were performed on Si(111)-H, Si(111)-Cl, and Si(111)-CH 3 models containing an infinite 〈112 h〉 or 〈1 h1 h2〉 step edge (Figure 2). 12 The difference in strain between these two step edges was calculated per edge site. The strain energy difference was found to be small for Si(111)-H, but not for Si(111)-Cl and Si(111)-CH 3 , which exhibit a strong preference for 〈1 h1 h2〉 (Table 1, 2nd column).…”

“…The 〈1 h1 h2〉 structure (b) has reconstructed to have its substituents perpendicular to the edge surface and to lower its energy. 12 bulk…”

“…They did not observe full stacking faults, but with their method (exposure of a DAS 7 × 7 Si(111) surface to Cl 2 gas at 673-773 K), the (7 × 7) f (1 × 1) transformation occurs predominantly along step edges. 12 In some cases, they may have also examined the surface structure before it transformed fully into a 1 × 1 Si(111)-Cl. Since the CH 3 -MgCl Grignard reagent in our experiments is appreciably larger than Cl 2 , it is plausible that steric interactions would play an even more significant role in the formation of a stacking fault in our Si(111)-CH 3 samples.…”