Adatom bonding at Si and SiC surfaces

Conference · Fri Dec 01 04:00:00 EST 1995

OSTI ID:126258

Smith, A; Yan, H; Jonsson, H ^[1]

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1. Univ. of Washington, Seattle, WA (United States)

We present ab initio density functional calculations on (100) surfaces of Si and {beta}-SiC. A Si adatom on the dimer-reconstructed Si(100) surface preferably binds at non-crystallographic sites, often forming 3-membered rings and five-fold coordinated subsurface atoms. A surface dimer stays intact when an adatom is placed on top, but an equally stable broken dimer configuration exists with the adatom sitting closer to the surface. Several surface reconstructions were investigated for Si and C rich SiC surfaces and the energetics of chemical reactions involved in CVD crystal growth evaluated. The lowest energy C-terminated surface is a c(2 x 2) structure with triply bonded carbon dimers in a bridging position between neighboring underlying silicon dimers. Added hydrogen atoms bond to the carbon dimers, resulting in a lengthened double bonded dimer. The most stable Si-terminated surface is a (3 x 2) reconstruction with a 1/3 monolayer excess of silicon forming extra dimers above an underlying (1 x 2) dimer row structure.

• OSTI ID: 126258
• Report Number(s): CONF-950402--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALCULATION METHODS
CHEMICAL BONDS
CHEMICAL VAPOR DEPOSITION
CRYSTAL GROWTH
DIMERS
SEMICONDUCTOR MATERIALS
SILICON
SILICON CARBIDES
SURFACE PROPERTIES