Positron trapping rates and their temperature dependencies in electron-irradiated silicon

Mascher, P.; Dannefaer, S.; Kerr, D.

doi:10.1103/physrevb.40.11764

Cited by 133 publications

(36 citation statements)

References 19 publications

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“…This is confirmed both from experiments [57,58] and theoretical studies [30]. In fact, first-principle calculations [30] show that the structures of m vacancies (m 3) reconstruct in order to form fourfold coordinated structures with no dangling bonds.…”

Section: B V 2 H 8 (H 2 @V 2 H 6 )supporting

confidence: 61%

Energetic and vibrational analysis of hydrogenated siliconmvacancies above saturation

Ghasemi

Lenosky²,

Amsler

et al. 2014

Phys. Rev. B

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We present a systematic study on hydrogenated silicon m vacancies above saturation. For each system a global geometry optimization search for low-lying local minima is performed using a newly developed SiH tight binding model. Subsequently a large number of low-energy structures are examined by density functional calculations using a minimal basis set. Finally the energetically favorable structures are reexamined using a systematically extendable basis set with local, semilocal, and hybrid exchange-correlation functionals. Particular attention is paid to the divacancy to which the Raman peak at 3822 cm −1 associated with the H 2 molecule had previously been assigned. Both the energetics and vibrational analysis of divacancy-related stable configurations suggest a revision of the above conclusion.

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Section: B V 2 H 8 (H 2 @V 2 H 6 )supporting

confidence: 61%

Energetic and vibrational analysis of hydrogenated siliconmvacancies above saturation

Ghasemi

Lenosky²,

Amsler

et al. 2014

Phys. Rev. B

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“…37 In addition to dopants, interstitial oxygen atoms also trap monovacancies, whereupon substitutional oxygen is formed ͑A centers͒, but these centers could not be detected optically due to saturation of absorption arising from doping. These defects are not detected by PAS at room temperature, 38 but are a potential source of migrating oxygen above 250°C where they disappear. 39 We now turn to the role of impurities on the annealing of irradiation-produced vacancies.…”

Section: Samplementioning

confidence: 95%

Annealing of electron-, proton-, and ion-produced vacancies in Si

et al. 2006

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Positron lifetime and Doppler measurements were performed on float-zone-refined and variously doped Czochralski-grown Si. The samples were irradiated by various particles ͑e − , p, Kr͒ with energies between 2 MeV and 245 MeV. Electron or proton irradiation gave rise to divacancies, whereas the damage from ion implantation ͑Kr͒ was mainly in the form of four-vacancy clusters, with only a small fraction of vacancies in the form of divacancies. In the case of impurity-lean Si, detailed isothermal annealing at various temperatures between 125°C and 500°C showed that after an initial fast decrease in divacancy concentration, a much slower process of vacancy agglomeration took place. At 450°C agglomeration steadily progressed even after 30 h of annealing at which point the average cluster size corresponded to ten monovacancies. In impurity-rich Si, containing oxygen and dopants, there is nearly no initial decrease in vacancy concentration, and isothermal and isochronal annealings showed that vacancy agglomeration was also nearly absent. Doppler data showed that vacancy-dopant complexes slowly acquired oxygen as annealing progressed, and these complexes survived annealing at 500°C for many hours. Measurements between 8 K and 530 K on samples containing divacancies, or larger clusters, showed a temperature dependence of the positron trapping rate that cannot be explained by the clusters being negatively charged, but can be explained if neutral clusters have a weakly bound positron state which at low temperatures makes trapping more efficient. Generally, the present positron experiments have given an indication for the type of defects that survive annealing at temperatures where electron paramagnetic resonance and infrared spectroscopy yield little useful information.

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“…The trapping rate of 5ϫ10 14 s Ϫ1 was used to estimate the defect concentration from the fitted diffusion length. 32 The sensitivity limit of the detection of defects was estimated to be 3ϫ10 18 cm Ϫ3 . A procedure described by Asoka-Kumar et al was used and assuming dϭ50 nm, S surf ϭ1.028 ͑as measured for the sample with n sb ϭ9.8ϫ10 19 cm Ϫ3 ) and S defect ϭ1.035 ͑cor-responding to Si divacancy, since the divacancy is the dominating defect in this sample: see the following text͒.…”

Section: Defects In Si Doped With Sbmentioning

confidence: 99%

Defect identification using the core-electron contribution in Doppler-broadening spectroscopy of positron-annihilation radiation

et al. 1996

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Reduction of background using a coincidence-detection system in Doppler-broadening spectroscopy of positron-annihilation radiation allows us to examine the contribution of high-momentum core electrons. The contribution is used as a fingerprint to identify chemical variations at a defect site. The technique is applied to study a variety of open volume defects in Si, including decorated vacancies associated with doping.

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Positron trapping rates and their temperature dependencies in electron-irradiated silicon

Cited by 133 publications

References 19 publications

Energetic and vibrational analysis of hydrogenated siliconmvacancies above saturation

Energetic and vibrational analysis of hydrogenated siliconmvacancies above saturation

Annealing of electron-, proton-, and ion-produced vacancies in Si

Defect identification using the core-electron contribution in Doppler-broadening spectroscopy of positron-annihilation radiation

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