Surface Structure of Si

Table 7. Calculated surface free energy y and surface stress x on various surface structures of Si and Ge. ...

It should be emphasized that under these conditions the surface structure of Si(lOO) is substantially different from oxidized Si(lOO) which is polar and in effect hydrophilic [359]. This is nicely demonstrated in Fig, 14.7, where for SI and S3 the cPAC values are shown for bare and oxidized Si(lOO) samples. These data were obtained from AFM experiments of the peptides SI and S3 interacting with Si(lOO) and GaAs(lOO) substrates in solution [340]. The main result is that the binding of SI to oxidized GaAs(lOO) and Si(lOO) surfaces is virtually independent of the substrate type which is widely screened by the top oxygen layer. The different adhesion propensities to the bare (hydrated) substrates lead to the conclusion that oxidation does not strongly progress on timescales of the peptide adsorption process. 

Flamers R J, Tromp R M and Demuth J M 1986 Surface electronic structure of Si(111)-7 7 resolved in real space Phys. Rev. Lett. 56 1972... 

Information about the surface reaction coefficients of radicals Si H2 +i where n > 1 is scarce. Because the structure of these radicals is similar to that of SiH3, the same surface reaction coefficients are used. It is assumed that if Si H2 i+1 radicals recombine at the surface with a hydrogen atom, a Si H2,+2 neutral is formed and is reflected into the discharge. Another possibility is the surface recombination of Si,H2 +i radicals with physisorbed Si ,H2m + i radicals at the surface. Matsuda et al. [137] have shown that the probability of surface recombination of SiHs with physisorbed SiH3 decreases with increasing substrate temperature. Doyle et al. [204] concluded that at a typical substrate temperature of 550 K, SiH3 radicals mainly recombine with physisorbed H atoms. 

Tromp, R. M., Hamers, R. J., and Demuth, J. E. (1986a). Quantum states and atomic structure of Si surface Science 234, 304-309. 

We begin by reviewing the surface structure of the most commonly studied crystal faces of these materials. We will then briefly discuss the oxidation of both silicon and germanium, then review the passivation of silicon and germanium surfaces. In addition, we explore the reactivity of Si, Ge, and to a lesser extent GaAs and InP, toward various organic molecules that can be used to functionalize the surface and impart new properties to the semiconductor. 

Alkynes have also been shown to form the [2 + 2] cycloaddition product. Acetylene (H—C=C—H), the simplest alkyne, forms an interesting adsorption case, because the specific adsorption geometries of acetylene on Si(100)-2 x 1 have been debated [11,201,207,210,224-236]. Acetylene was first found experimentally to form a [2 + 2] C=C cycloaddition product that exhibits a cyclobutene-like surface structure on Si(100)-2 x 1 [210,227]. Later STM measurements revealed that at least two different surface products were present [228,231,233], and identified a product that is oriented perpendicularly to the dimer row. From these images, it was argued that in addition to an intradimer [2 + 2] C=C cycloaddition geometry, acetylene also forms a surface adduct that bridges two dimers along a row. Several theoretical... 

Both thermal treatments appeared to have similar effects on the straw ash surface chemistry. The main inorganic elements constituting the surface structure of the heated satrqiles were in all cases, including the leached samples, K. and Si, followed by Ca. Other components of the modified ash structure included small amounts of S and Cl, and trace amounts of Na, Mg, Fe and P,... 

P. Allongue, V. Kieling, and H. Gerischer, Atomic structure of Si surfaces etched in Triton/NaOH solutions, J. Phys. Chem. 99, 9472, 1995. 

Recently, Zunger and coworkers [18, 58-63] employed the semi-empirical pseudopotential method to calculate the electronic structure of Si, CdSe [60] and InP [59] quantum dots. Unlike EMA approaches, this method, based on screened pseudopotentials, allows the treatment of the atomistic character of the nanostructure as well as the surface effects, while permitting multiband and intervalley coupling. The atomic pseudopotentials are extracted from first principles LDA calculations on bulk solids. The single particle LDA equation,... 

Fine control of macro- and microstructures in Si-multicrystal ingots may be needed for the future. The crystal structure of Si-multicrystal is largely different from Si single crystal, as illustrated by formation of grain boundaries and the distribution of crystallographic orientations on a wafer surface. 

Roche J.R., Ramonda M., Thibaudau F., Dumas P., Mathiez P., Salvan F. and Allongue P. (1994), Structure of Si(lll) surfaces etched in 40% NH4F influence of the doping . Microscopy Microanalysis Microstructures 5, 291-299. 

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