Transmission-ion-channeling investigation of Ge adsorbed on the Si(100) surface at submonolayer coverage

Abstract

Transmission ion channeling has been used to investigate the bonding geometry of Ge on the Si(100)-2 X 1 surface at a coverage of 0.6 ML. It is shown that this surface is terminated by asymmetric Ge-Ge dimers with a bond length of 2.6 A and a tilt of 12', in agreement with previous results. The structure of the surface is shown to vary with Ge coverage, which is possibly attributable to the strain induced during growth by the 4% lattice mismatch between Ge and Si.

Ab Initiostudy of the mixed dimer formation in Ge growth on Si(100)

“…24 Similarly, a Ge-Ge dimer bond length of 2.6 Å and a buckling angle of 12°were estimated in a transmissionion-channeling study. 25 In contrast, a surface-extended x-rayabsorption fine-structure study 26 reported that the Ge-Ge dimers are symmetric with a bond length of 2.51 Å . Compared to previous and our theoretical results, the experimental values for Ge-Ge dimers showed larger dimer bond lengths and smaller buckling angles.…”

A Theoretical Study of the Structure and Thermochemistry of 1,3-Butadiene on the Ge/Si(100)-2 × 1 Surface

“…Different results have been reported for the geometry of the dimers on the Ge/Si(100)-2 × 1 surface. Theory predicted the Ge−Ge homodimer bond lengths between 2.38 and 2.51 Å and buckling angles from 12.7° to 20.4°. − On the other hand, experiments using various techniques obtained Ge−Ge bond lengths of 2.40−2.60 Å and buckling angles from 0° to 17.8°. − In general, theoretical calculations predict shorter Ge−Ge bond lengths than experimental measurements. There are fewer studies on the geometry of the Ge−Si heterodimer on the Ge/Si(100)-2 × 1 surface.…”

“…[12][13][14][15][16][17][18][19] On the other hand, experiments using various techniques obtained Ge-Ge bond lengths of 2.40-2.60 Å and buckling angles from 0°to 17.8°. [20][21][22][23][24][25][26][27][28][29][30] In general, theoretical calculations predict shorter Ge-Ge bond lengths than experimental measurements. There are fewer studies on the geometry of the Ge-Si heterodimer on the Ge/Si(100)-2 × 1 surface.…”

Sensitivity of Reflectance Anisotropy Spectroscopy to the Orientation of Ge Dimers on Vicinal Si(001)

“…The growth of Ge on Si(001) proceeds in a similar way to Si homoepitaxy for the first few monolayers producing a layer-by-layer growth mode with Ge dimers oriented orthogonally on subsequent layers [13][14][15][16]. Scanning tunneling microscopy (STM) reveals that dimer vacancy rows are formed to alleviate strain at Ge coverages of approximtely 1.5 monolayer (ML), producing a ͑2 3 n͒ rather than a ͑2 3 1͒ reconstruction, where n͑$3͒ refers to the separation between adjacent dimer vacancy rows [17].…”