Raman Studies of Hydrogen Passivation in Silicon

1987 ◽  
Vol 104 ◽  
Author(s):  
M. Stutzmann ◽  
C. P. Herrero
Keyword(s):  
Raman Scattering ◽  
Optical Phonon ◽  
Vibrational Frequency ◽  
Crystalline Silicon ◽  
Structural Models ◽  
Uniaxial Stress ◽  
Vibrational Modes ◽  
Hydrogen Passivation ◽  
Raman Active Mode ◽  
Localized Vibrational Modes

ABSTRACTWe have studied the hydrogen passivation of boron acceptors in bulk crystalline silicon with Raman scattering. Upon hydro-genation, distinct changes in the optical phonon lineshape and the localized vibrational modes of boron are observed. The hy-drogen in the passivated region gives rise to a specific Raman-active mode, whose vibrational frequency depends strongly on temperature and uniaxial stress. Implications of these results on possible structural models are discussed.

Determination of the Bonding Configurations of Carbon Acceptors in InxGa1−xAs and AlxGa1−xAs

1995 ◽  
Vol 379 ◽  
Author(s):  
R. E. Pritchard ◽  
R.C. Newman ◽  
J. Wagner ◽  
M. Maier ◽  
A. Mazuelas ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Nearest Neighbors ◽  
Ir Absorption ◽  
Vibrational Modes ◽  
High Solubility ◽  
Compositional Range ◽  
Local Environments ◽  
Localized Vibrational Modes

ABSTRACTThe local environments of CAs acceptors in InxGa1−xAs and AlxGa1−xAs have been determined from the localized vibrational modes (LVMs) of both isolated CAs impurities and H-CAs pairs using infrared (IR) absorption and Raman scattering techniques. In as-grown layers of InxGa1−xAs (x<0.1), a single LVM due to isolated CAs acceptors was observed. The introduction of hydrogen led to the formation of H-CAs pairs and a single A1−-mode (stretch) and a single A1+-mode (XH) were observed for the InxGa1−xAs layers. All the LVMs were identified with carbon in CAsGa4 cluster configurations implying that less than 5 % of the detectable carbon atoms were present in clusters incorporating one or more CAs-In bonds. For AlxGa1−xAs, five stretch modes and five X-modes of the H-CAs pairs were observed for 0<x<1 and each mode was assigned to configurations for which the originally unpaired CAs had 0,1,2,3 or 4 Al nearest neighbors. These results show that carbon does not appear to form bonds with In atoms for the InxGa1−xAs samples investigated and this can explain the difficulty found in incorporating CAs acceptors in InxGa1−xAs with x>0.1 for some growth techniques. CAs acceptors can form strong bonds with both Al and Ga atoms, however, leading to a high solubility of carbon in AlxGa1-xAs over the full compositional range.

Silicon Delta Doping in GaAs: An Ongoing Enigma

1995 ◽  
Vol 378 ◽  
Author(s):  
R. C. Newman ◽  
M. J. Ashwin ◽  
J. Wagner ◽  
M. R. Fahy ◽  
L. Hart ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Surface Diffusion ◽  
Long Range ◽  
Electron Trap ◽  
Ir Absorption ◽  
Vibrational Modes ◽  
Thermally Activated ◽  
Delta Doping ◽  
Antisite Defects ◽  
Localized Vibrational Modes

AbstractInfrared (IR) absorption and Raman scattering are reported from the localized vibrational modes (LVM) of Al and Si δ-layer superlattices in MBE (100) GaAs grown at 400°C as a function of the total areal concentrations, [A1]A and [Si]A respectively. The Al superlattices show the expected behavior on passing from sub-monolayer (ML) to thicker layers (thin AlAs) since the impurities still occupy only Ga-sites. The behavior is very different from that found for Si δ-layers. In addition to SiGa reported previously, we now show that SiAs, SiGa-SiAs pairs and the electron trap Si-X are also present in Si δ-layers and superlattices for 0.05 ≤ [Si]A≤ 0.5 ML. The conductivity of these structures and the concentrations of substitutional Si in GaAs at all sites fall to zero for [Si]A> 0.5 ML but a Raman feature at 470–490 cm−1, attributed to the vibrations of covalent Si-Si bonds is then detected. This feature is not observed in structures containing very closely spaced dilute (0.01 ML) Si δ-planes. It is inferred that long-range Si diffusion does not occur in the bulk crystal, although there could be surface diffusion during Si deposition. The maximum measured carrier concentrations are always less than 2 × 1019 cm−3, the DX limit. The redistribution of Si amongst the various lattice sites is discussed in terms of SiGa DX-like displacements occurring during growth, followed by local thermally activated diffusion jumps. It is speculated that AsGa antisite defects and Ga-vacancies are produced by this process. The reason why the Si δ-layer is non-conducting remains unclear.

Raman scattering from localized vibrational modes of boron impurities in silicon

1971 ◽  
Vol 9 (20) ◽  
pp. 1719-1721 ◽  
Author(s):  
W. Nazarewicz ◽  
M. Balkanski ◽  
J.F. Morhange ◽  
C. Sébenne
Keyword(s):  
Raman Scattering ◽  
Vibrational Modes ◽  
Localized Vibrational Modes

Effects of uniaxial stress and electric fields on localized vibrational modes of H - and D - ions in CaF 2

1967 ◽  
Vol 297 (1451) ◽  
pp. 503-519 ◽  
Keyword(s):  
Excited States ◽  
Electric Fields ◽  
Ground State ◽  
Low Temperatures ◽  
Second Harmonic ◽  
Uniaxial Stress ◽  
Vibrational Modes ◽  
External Perturbations ◽  
Vibrational Levels ◽  
Localized Vibrational Modes

This paper contains a description of the effects of stress and electric fields on the fundamental and second harmonic localized vibrational levels of H - and D - ions in CaF 2 . Electric dipole transitions are allowed from the singlet Γ 1 ground state to the triply degenerate Γ 5 excited states and the absorption lines are sufficiently narrow at low temperatures ( ca . 1 cm -1 ) to enable splitting of the Γ 5 states by the external perturbations to be measured. The measured splittings are a factor of approximately √2 smaller for D - ions than for H - ions. Transitions to the second harmonic Γ 3 and Γ 1 levels, which cannot be observed in unperturbed crystals, have been found in stressed crystals due to stress induced admixture of the nearby second harmonic Γ 5 state.

scholarly journals Raman Scattering from Localized Vibrational Modes in GaP

1970 ◽  
Vol 25 (17) ◽  
pp. 1184-1187 ◽  
Author(s):  
D. T. Hon ◽  
W. L. Faust ◽  
W. G. Spitzer ◽  
P. F. Williams
Keyword(s):  
Raman Scattering ◽  
Vibrational Modes ◽  
Localized Vibrational Modes

Electron-Phonon Interaction and Joule Heating in Nanostructures

2008 ◽  
Author(s):  
Eric Pop
Keyword(s):  
Carbon Nanotubes ◽  
Electric Fields ◽  
Joule Heating ◽  
Optical Phonon ◽  
Phonon Transport ◽  
Phonon Energy ◽  
Strained Silicon ◽  
Vibrational Modes ◽  
Optical Phonons ◽  
Ambient Gas

The electron-phonon energy dissipation bottleneck is examined in silicon and carbon nanoscale devices. Monte Carlo simulations of Joule heating are used to investigate the spectrum of phonon emission in bulk and strained silicon. The generated phonon distributions are highly non-uniform in energy and momentum, although they can be approximately grouped into one third acoustic (AC) and two thirds optical phonons (OP) at high electric fields. The phonon dissipation is markedly different in strained silicon at low electric fields, where certain relaxation mechanisms are blocked by scattering selection rules. In very short (∼10 nm) silicon devices, electron and phonon transport is quasi-ballistic, and the heat generation domain is much displaced from the active device region, into the contact electrodes. The electron-phonon bottleneck is more severe in carbon nanotubes, where the optical phonon energy is three times higher than in silicon, and the electron-OP interaction is entirely dominant at high fields. Thus, persistent hot optical phonons are easily generated under Joule heating in single-walled carbon nanotubes suspended between two electrodes, in vacuum. This leads to negative differential conductance at high bias, light emission, and eventual breakdown. Conversely, optical and electrical measurements on such nanotubes can be used to gauge their thermal properties. The hot optical phonon effects appear less pronounced in suspended nanotubes immersed in an ambient gas, suggesting that phonons find relaxation pathways with the vibrational modes of the ambient gas molecules. Finally, hot optical phonons are least pronounced for carbon nanotube devices lying on dielectrics, where the OP modes can couple into the vibrational modes of the substrate. Such measurements and modeling suggest very interesting, non-equilibrium coupling between electrons and phonons in solid-state devices at nanometer length and picoseconds time scales.

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