Chemisorption of sulfur on Ge(100)

Weser, T.; Bogen, A.; Konrad, B.; Schnell, R.D.; Schug, C.; Moritz, Wolfgang; Steinmann, W.

doi:10.1016/0039-6028(88)90609-7

Cited by 57 publications

(23 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, from an analysis of their core-level spectra they concluded that only 3/4 of a monolayer of Se atoms are in bridge positions. On the other hand, for S:Si(001) an ordered S adlayer could not be observed [72].…”

Section: Adsorption Of Group-v Elements: As and Sb On Si(o01) Sb On mentioning

confidence: 73%

“…The resulting structure shows a (1 x 1) LEED pattern. From the results of core-level and photoemission spectroscopy [67], the authors favour a bonding geometry with S atoms acting like bridges between Ge atoms of the topmost layer. We have carried out energy minimizations for the chemisorption of S on Ge(001) setting out from several start geometries [68].…”

Section: Adsorption Of Group-vl Elements: S and Se On Si(o01) And Ge(mentioning

confidence: 97%

See 1 more Smart Citation

Theory of adsorption: Ordered monolayers from Na to Cl on Si(001) and Ge(001)

Krüger

Pollmann

1994

Appl. Phys. A

View full text Add to dashboard Cite

Abstract. First principles calculations of clean and adsorbate-covered surfaces of Si(001) and Ge(001) are reported. Chemical trends in the adsorption of ordered Na, K, Ge, As, Sb, S, Se and CI overlayers are discussed. The calculations are based on the local-density approximation and employ non-local, norm-conserving pseudopotentials together with Gaussian orbital basis sets. The semi-infinite geometry of the substrate is properly taken into account by employing our scattering theoretical method. From total-energy minimization calculations we obtain optimal surface reconstructions which show asymmetric dimers for Si(001), Ge(001) and Ge:Si(001). For As:Si(001), Sb:Si(001) and Sb:Ge(001), we find symmetric adatom dimers in the equilibrium geometries. S or Se adlayers are found to be adsorbed in bridge positions forming a (1 x 1) unit cell with a geometry very close to the configuration of a terminated bulk lattice. C1 atoms adsorb on top of the dangling bonds of symmetric Si dimers residing in the first substrate-surface layer. Our calculations for Na:Si(001) and K:Si(001) confirm valleybridge site adsorption for half monolayer coverage. For full monolayer alkali-metal coverage, adsorption in pedestal and valley-bridge positions is found to be energetically most favourable. The calculated optimal adsorption configurations are in excellent agreement with a whole body of recent experimental data on surface-structure determination. For these structural models, we obtain electronic surface band structures which agree very good with a wealth of data from angle-resolved photoemission spectroscopy investigations. The adsorption of adlayers at semiconductor surfaces has been under intensive study in recent years. These investigations are motivated by fundamental physical reasons and important technological applications. In basic research, semiconductors are interesting substrates for adsorption systems due to the unsaturated directional bonds at their surfaces. This allows the formation of chemical compounds which are neither stable as small, isolated molecules nor as extended solids. The technological interest ranges from homoand heteroepitaxy and growth, via surface passivation and doping to dry etching and photo-surface cleaning. For example, the quality of the heteroepitaxial growth of GaAs on Si is determined by the initial stage of this process which consists in formation of As adlayers. Furthermore, surface passivation may involve As, S or Se atoms. In the fabrication of electronic devices, dry etching and photo-surface cleaning is carried out by the reaction of C1 on Si. The adsorption of alkali metals in the range of monolayer coverage leads to a drastic reduction of the ionization energy. These systems have important applications as high-efficiency emitters. They are also widely discussed in the context of the Schottky-barrier problem [1].

show abstract

Section: Adsorption Of Group-v Elements: As and Sb On Si(o01) Sb On mentioning

confidence: 73%

Section: Adsorption Of Group-vl Elements: S and Se On Si(o01) And Ge(mentioning

confidence: 97%

Theory of adsorption: Ordered monolayers from Na to Cl on Si(001) and Ge(001)

Krüger

Pollmann

1994

Appl. Phys. A

View full text Add to dashboard Cite

show abstract

“…We have also displayed the photoelectron spectra measured along the M Ϫ⌫ ϪJ symmetry direction. 26 Our calculated surface states S 3 s , S 4 s , and S 5 s can be compared with the experimental spectra. While the dispersion of the calculated and measured states are similar, we note that the calculated states are systematically higher in energy than the measured states.…”

Section: H 2 S On Ge(001)-(1؋2)mentioning

confidence: 98%

Adsorption of partially and fully dissociatedH2Smolecules on the Si(001) and Ge(001) surfaces

Çakmak

Srivastava

1999

Phys. Rev. B

View full text Add to dashboard Cite

Ab initio calculations, based on pseudopotentials and the density functional theory, have been made to investigate the equilibrium atomic geometry, electronic states, and bonding of the H 2 S molecule on the Si͑001͒ and Ge͑001͒ surfaces within two dissociative adsorption geometries. First we consider adsorption of partially dissociated species (SH) Ϫ and H ϩ onto the Si or Ge dimer with a (1ϫ2) surface periodicity. Secondly, we consider adsorption of fully dissociated species S and 2H on the surface with a (1ϫ2) periodicity but without dimer formation. In general, the adsorption of H 2 S on the Si͑001͒ and Ge͑001͒ surfaces shows similar behavior. For both geometries studied here, the fundamental band gap is free of surface states, with the highest occupied state lying below the valence band maximum. ͓S0163-1829͑99͒14531-4͔

show abstract

“…The surface ordering reported for the wet (NH 4 ) 2 S treatment is a (1 Â 1) reconstruction, 3,5 while the gas phase reaction of H 2 S results in a (2 Â 1) reconstruction 2,9 and the gas phase adsorption of elemental S in a (1 Â 1) reconstruction. 7,8 The exact coverage of S on the Ge surface after the (NH 4 ) 2 S treatment varies for different reports. Lyman et al 4 ) measured the S coverage by XRF (2-3 monolayers) and the coherent coverage by X-Ray Standing Waves ($ 0.4 monolayers), the latter being defined as the total number of S atoms in registry with the Ge substrate.…”

mentioning

confidence: 99%

Atomic Layer Deposition of High-κ Dielectrics on Sulphur-Passivated Germanium

Sioncke

Lin

Brammertz

et al. 2011

J. Electrochem. Soc.

View full text Add to dashboard Cite

High mobility channels are currently being explored to replace the silicon channel in future CMOS technology nodes. However, until now the promising bulk properties are very difficult to translate into high transconductance due to a poor passivation of the interface between the gate dielectric and the channel. We have studied the S-passivation of the germanium surface combined with various high-permittivity dielectric gate stacks. (NH4)2S is used to achieve a S-terminated Ge surface. We found that the Ge/S/Al2O3 interface is superior to both the Ge/S/ZrO2 and Ge/S/HfO2 interfaces. Bi-layer stacks consisting of Ge/S/Al2O3/HfO2 or Ge/S/Al2O3/ZrO2 were built to achieve a gate stack with low EOT (Equivalent Oxide Thickness). In these bi-layer stacks, the Al2O3 thickness is reduced to a minimum without degradation of the interface properties. Rather thick Al2O3 interlayers (∼ 2 nm) are needed due to island growth on S-terminated Ge surface. A pMOSFET was built using a bi-layer gate stack (Ge/S/Al2O3/HfO2). The peak mobility of this device is > 200 cm2/Vs at an EOT of 1.5 nm.

show abstract

Chemisorption of sulfur on Ge(100)

Cited by 57 publications

References 28 publications

Theory of adsorption: Ordered monolayers from Na to Cl on Si(001) and Ge(001)

Theory of adsorption: Ordered monolayers from Na to Cl on Si(001) and Ge(001)

Adsorption of partially and fully dissociatedH2Smolecules on the Si(001) and Ge(001) surfaces

Atomic Layer Deposition of High-κ Dielectrics on Sulphur-Passivated Germanium

Contact Info

Product

Resources

About