He-implantation induced defects in Si studied by slow positron annihilation spectroscopy

Brusa, R. S.; Karwasz, Grzegorz P.; Tiengo, N; Zecca, Antonio; Corni, Federico; Nobili, C.

doi:10.1063/1.369555

Cited by 34 publications

(19 citation statements)

References 27 publications

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“…In the following, as in previous papers, 12 we present the data in a form that gives more direct information about positron trapping in open volume defects. With reference to Fig.…”

Section: A Analysis Of the Experimental Resultsmentioning

confidence: 98%

“…These observations have been interpreted as showing that the majority of vacancies produced during the implantation process is either passivated by He or involved in the formation of more complex defects. 12 In the samples implanted at lower dose only V 1 * stabilized by He-related defects survives. Due to the increased mobility of both He and vacancies during the implantation process, the V 1 * concentration is lower in the sample implanted at RT.…”

Section: As-implanted Samplesmentioning

confidence: 97%

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Formation of vacancy clusters and cavities in He-implanted silicon studied by slow-positron annihilation spectroscopy

et al. 2000

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The depth profile of open volume defects has been measured in Si implanted with He at an energy of 20 keV, by means of a slow-positron beam and the Doppler broadening technique. The evolution of defect distributions has been studied as a function of isochronal annealing in two series of samples implanted at the fluence of 5ϫ10 15 and 2ϫ10 16 He cm Ϫ2 . A fitting procedure has been applied to the experimental data to extract a positron parameter characterizing each open volume defect. The defects have been identified by comparing this parameter with recent theoretical calculations. In as-implanted samples the major part of vacancies and divacancies produced by implantation is passivated by the presence of He. The mean depth of defects as seen by the positron annihilation technique is about five times less than the helium projected range. During the successive isochronal annealing the number of positron traps decreases, then increases and finally, at the highest annealing temperatures, disappears only in the samples implanted at the lowest fluence. A minimum of open volume defects is reached at the annealing temperature of 250°C in both series. The increase of open volume defects at temperatures higher than 250°C is due to the appearance of vacancy clusters of increasing size, with a mean depth distribution that moves towards the He projected range. The appearance of vacancy clusters is strictly related to the out diffusion of He. In the samples implanted at 5ϫ10 15 cm Ϫ2 the vacancy clusters are mainly four vacancy agglomerates stabilized by He related defects. They disappear starting from an annealing temperature of 700°C. In the samples implanted at 2 ϫ10 16 cm Ϫ2 and annealed at 850-900°C the vacancy clusters disappear and only a distribution of cavities centered around the He projected range remains. The role of vacancies in the formation of He clusters, which evolve in bubble and then in cavities, is discussed.

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“…In the following, as in previous papers, 12 we present the data in a form that gives more direct information about positron trapping in open volume defects. With reference to Fig.…”

Section: A Analysis Of the Experimental Resultsmentioning

confidence: 98%

Section: As-implanted Samplesmentioning

confidence: 97%

Formation of vacancy clusters and cavities in He-implanted silicon studied by slow-positron annihilation spectroscopy

et al. 2000

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“…The SPAS is highly sensitive to open volume defects for the positron is apt to be trapped and annihilated in sites where the Coulomb core repulsion is a minimum. 12 The positrons were implanted in an energy range from 0.5 to 15 KeV. The Doppler broadening of the 511 KeV annihilation ␥ rays was measured at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Evolution of hydrogen and helium co-implanted single-crystal silicon during annealing

Duo¹,

Liu²,

Zhang³

et al. 2001

Journal of Applied Physics

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H + was implanted into single-crystal silicon with a dose of 1×1016/cm2 and an energy of 30 KeV, and then He+ was implanted into the same sample with the same dose and an energy of 33 KeV. Both of the implantations were performed at room temperature. Subsequently, the samples were annealed in a temperature range from 200 to 450 °C for 1 h. Cross-sectional transmission electron microscopy, Rutherford backscattering spectrometry/channeling, elastic recoil detection, and high resolution x-ray diffraction were employed to characterize the strain, defects, and the distribution of H and He in the samples. The results showed that co-implantation of H and He decreases the total implantation dose, with which the surface could exfoliate during annealing. During annealing, the distribution of hydrogen did not change, but helium moved deeper and its distribution became sharper. At the same time, the maximum of the strain in the samples decreased a lot and also moved deeper. Furthermore, the defects introduced by ion implantation and annealing were characterized by slow positron annihilation spectroscopy, and two positron trap peaks were found. After annealing, the maximum of these two peaks decreased at the same time and their positions moved towards the surface. No bubbles or voids but cracks and platelets were observed by cross-sectional transmission electron microscopy. Finally, the relationship between the total implantation dose and the fraction of hydrogen in total implantation dose was calculated.

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“…Every type of open volume defect is characterized by a typical Sd parameter. The Sd values were obtained [6,7] by the best fitting procedure and by the method of Ref. [10].…”

Section: Resultsmentioning

confidence: 99%

“…TEM was used on selected samples to identify the nanostructures. The distribution of open volume defects was found by positron annihilation spectroscopy (PAS) [6,7].…”

Section: Introductionmentioning

confidence: 99%

Vacancy Cluster Distributions in He Implanted Silicon Studied by Slow Positron Annihilation Spectroscopy

Brusa

1999

Acta Phys. Pol. A

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He-implantation induced defects in Si studied by slow positron annihilation spectroscopy

Cited by 34 publications

References 27 publications

Formation of vacancy clusters and cavities in He-implanted silicon studied by slow-positron annihilation spectroscopy

Formation of vacancy clusters and cavities in He-implanted silicon studied by slow-positron annihilation spectroscopy

Evolution of hydrogen and helium co-implanted single-crystal silicon during annealing

Vacancy Cluster Distributions in He Implanted Silicon Studied by Slow Positron Annihilation Spectroscopy

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