In Studies of the Electron-Irradiated Silicon Crystal Grown in Hydrogen Atmosphere

Shi, Tiansheng; Bai, G. R.; Qi, Mw; Zhou, Jieying

doi:10.4028/www.scientific.net/msf.10-12.597

Cited by 22 publications

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“…These results show that interstitial H 2 in Si reacts with V and I to form IR-active centers, as observed experimentally [54,63,64]. V and/or I are present in the sample in above-equilibrium concentrations during a variety of processes such as electron irradia-1 ) The idea was suggested to us by R.C.…”

Section: Interactions Of V and I With H 2 Formation Of H *supporting

confidence: 64%

“…A transition from`hidden hydrogen' to H * 2 following 2 MeV electron irradiation has first been found in [63]. Experimental evidence shows that a transition from H 2 to states involving Si±H bonds results from radiation damage [64]. Such states include fVY HY Hg (a vacancy decorated with two H atoms [65]) and fIY HY Hg (two H atoms trapped at a self-interstitial [66], Fig.…”

Section: Interactions Of V and I With H 2 Formation Of H *mentioning

confidence: 99%

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Structure and Dynamics of Point Defects in Crystalline Silicon

Estreicher

2000

phys. stat. sol. (b)

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Section: Interactions Of V and I With H 2 Formation Of H *supporting

confidence: 64%

Section: Interactions Of V and I With H 2 Formation Of H *mentioning

confidence: 99%

Structure and Dynamics of Point Defects in Crystalline Silicon

Estreicher

2000

phys. stat. sol. (b)

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“…Indeed, early theory predicted [4,5] that the H 2 molecule is stable at the tetrahedral interstitial (T) site where it should be IR inactive. It has also been shown that hidden hydrogen can be rendered very visible by electron irradiation [6] or other damage-inducing treatment. Molecular-dynamics (MD) simulations of interstitial H 2 interacting with a vacancy or a self-interstitial show the dissociation of the molecule and the formation of Si-H bonds at the defect [7,8].…”

Section: Introductionmentioning

confidence: 99%

Dynamics of interstitial hydrogen molecules in crystalline silicon

Estreicher

Wells

Fedders

et al. 2001

J. Phys.: Condens. Matter

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The static and dynamic properties of interstitial H2, HD and D2 molecules in crystalline silicon are obtained from ab initio molecular-dynamics simulations with atomic-like basis sets. The static (T = 0) calculations agree with those of most other authors: the centre of mass (CM) of H2 is at the tetrahedral interstitial (T) site, the molecule is a nearly-free rotator, and the activation energy for diffusion is 0.90 eV. However, these results fail to explain a number of experimental observations, such as why H2 is infrared (IR) active, why the expected ortho/para splitting is not present, why the symmetry is C1, why the piezospectroscopic tensors of H2 and D2 are identical or why the exposure to an H/D mix results in a single HD line which is not only at the wrong place but also much weaker than expected. In the present work, we extend the static calculations to include the constant-temperature dynamics for H2 in Si. At T>0 K, the CM of the molecule no longer remains at the T site. Instead, H2 `bounces' off the walls of its tetrahedral cage and exchanges energy with the host crystal. The average position of the CM is away from the T site along ⟨100⟩. Under uniaxial stress, the CM shifts off that axis and the molecule has C1 symmetry. The H-H stretch frequency calculated from the Fourier transform of the v-v autocorrelation function is close to the measured one. Since the potential energy experienced by H2 in Si near the T site is very flat, we argue that H2 should be a nearly free quantum mechanical rotator. Up to room temperature, only the j = 0 and j = 1 rotational states are occupied, H2 resembles a sphere rather than a dumbbell, the symmetry is determined by the position of the CM and HD is equivalent to DH in any symmetry. The rapid motion of the CM implies that an ortho-to-para transition will occur if a large magnetic moment is nearby. Several candidates are proposed. Since nuclear quantum effects are not included in our calculations, we cannot address the possibility that the observed vibrational spectrum of H2 results from a tunnelling excitation as proposed by Stoneham.

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“…The above results are much different from those obtained by other authors. Shi et al 11) first studied interaction between H and point defects in electron-irradiated Si from the measurements of optical absorption spectra. They doped H in their crystals by growing them in a hydrogen atmosphere.…”

mentioning

confidence: 99%

Self-Interstitial in Electron-Irradiated Si Detected by Optical Absorption Due to Hydrogen Bound to It

Suezawa¹

1998

Jpn. J. Appl. Phys.

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We studied the interaction between hydrogen and point defects generated by electron irradiation of Si by means of optical absorption measurement. Specimens were prepared from n-type Si crystals. Those specimens were doped with hydrogen by annealing in a hydrogen atmosphere at 1200 • C followed by quenching and were subsequently irradiated with 3 MV electrons at room temperature. We observed their optical absorption spectra at about 6 K with a resolution of 0.25 cm −1 . Many optical absorption peaks were observed in electron-irradiated specimens. Most of those peaks disappeared at around 300 • C due to isochronal annealing. On the other hand, new optical absorption lines appeared at 2223 cm −1 and 2166 cm −1 after annealing at high temperature, namely above 150 • C. The former is known to be due to a complex of one self-interstitial atom and 4 hydrogen atoms. We propose that the 2166 cm −1 peak is due to a complex of one self-interstitial atom and three hydrogen atoms. These results clearly show that complexes of self-interstitials exist after electron-irradiation of Si and they dissociate above 150 • C.

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In Studies of the Electron-Irradiated Silicon Crystal Grown in Hydrogen Atmosphere

Cited by 22 publications

References 0 publications

Structure and Dynamics of Point Defects in Crystalline Silicon

Structure and Dynamics of Point Defects in Crystalline Silicon

Dynamics of interstitial hydrogen molecules in crystalline silicon

Self-Interstitial in Electron-Irradiated Si Detected by Optical Absorption Due to Hydrogen Bound to It

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