Investigation of band bending in silicon by slow positron lifetime measurements

Duffy, J. A.; Bauer-Kugelmann, W.; Kögel, G.; Triftshäuser, W.

doi:10.1016/s0169-4332(96)01062-8

Cited by 13 publications

(6 citation statements)

References 8 publications

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“…If we assume a constant width of the abruptly falling region d, which is about 20 µm as seen in [11], the increase of the electric field with respect to time before reaching the maximum measured at different temperatures shown in figure 2 can be fitted with equation (7). The fitted curves are shown in figure 2 and reasonably represent the experimental data.…”

Section: Thermal Electron Emission From the Deep-level Donor El2supporting

confidence: 54%

“…Besides their use as a vacancy probe in semiconductors [1][2][3], different techniques in positron annihilation spectroscopy (PAS) have also been employed to reveal the internal electric field at buried internal interfaces [4][5][6][7][8]. In the case of the metal-semiconductor contact, positrons implanted into the sample can drift back to the interface under the action of an internal electric field, get trapped by voids at the interface, and annihilate from these open volume defect sites.…”

Section: Introductionmentioning

confidence: 99%

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A study of the electric field transient at the Au/semi-insulating GaAs contact under an alternating current square-pulse bias

Ling¹,

Fung²,

Beling³

et al. 2002

J. Phys.: Condens. Matter

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Positron lifetime spectroscopy combined with a 50 V AC applied square-wave bias has been used to probe the electric field in the 2 μm region next to an Au/SI-GaAs contact. The electric fields spatially and time averaged over the reverse half-period at different temperatures (255–295 K) and pulsing periods (∼1 ms–10 ks) have been obtained using a numerical differentiation technique. It is found that within the temperature range studied, the electric field first increases as a function of time to a maximum of about 10 kV cm−1 and then decreases, before finally saturating at the DC value of 7 kV cm−1. The increase of the electric field with time is attributed as previously to the electron emission from the EL2 defect. The subsequent electric field decrease is associated with the onset of a thermally activated process with an energy barrier of 1.03 ± 0.15 eV. This process, which causes the neutralization of the space charge region, may be tentatively attributed to the recombination centres EL5 or EL6.

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Section: Thermal Electron Emission From the Deep-level Donor El2supporting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

A study of the electric field transient at the Au/semi-insulating GaAs contact under an alternating current square-pulse bias

Ling¹,

Fung²,

Beling³

et al. 2002

J. Phys.: Condens. Matter

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“…9 This surface field region is so thin that some positrons are still able to penetrate the potential barrier. In the case of the samples without F, barrier penetration and reaching the surface are more likely because the positrons have longer effective diffusion lengths in the absence of the FV layer sink, and approach the barrier more often.…”

mentioning

confidence: 99%

Fluorine-vacancy complexes in ultrashallow B-implanted Si

Abdulmalik

Coleman

Cowern

et al. 2006

Applied Physics Letters

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Shallow fluorine-vacancy ͑FV͒ complexes in Si have been directly observed using variable-energy positron annihilation spectroscopy and secondary ion mass spectrometry. The FV complexes, introduced to combat the deactivation and transient-enhanced diffusion of ultrashallow boron, were observed in preamorphized Si wafers implanted with 0.5 keV B and 10 keV F ions at a dose of 10 15 cm −2 , and then annealed isothermally at 800°C for times ranging from 1 to 2700 s. The results are in agreement with a model which predicts that the complexes are of the form F 3n V n , with n most probably being 1 and/or 2. © 2006 American Institute of Physics. ͓DOI: 10.1063/1.2335594͔Interest in the beneficial consequences of implanting F ions in Si has grown in recent years as defect engineering has been developed to meet the continuing challenges of device miniaturization. The application of particular interest here concerns ultrashallow B implantation into preamorphized Si regrown via solid-phase epitaxy ͑SPE͒; efficient activation of the B while limiting its diffusion is the key to the formation of ultrashallow junctions. Recent work by Cowern et al. 1 showed that F in B-implanted Si can form clusters that trap interstitals ͑I͒ released from the band of end-of-range ͑EOR͒ defects, which in turn both retard the transient enhanced diffusion of B implants and significantly decrease their deactivation. Kham et al. 2 linked F found at half the projected ion range to the formation of clusters of F with vacancies ͑V͒ in this region. Other studies conclude that FV or FI complexes suppress B diffusion by reducing I emission from extended I defects generated by implantation. 3,4 Variable-energy positron annihilation spectroscopy ͑VE-PAS͒ is used here to probe the nature of the complexes formed by the implanted F ions. The technique has been used to identify FV complexes in thermally treated F-implanted Si. 5,6 VEPAS measures the Doppler broadening of the 511 keV ␥-ray annihilation line, whose extent is determined by the average momentum of the electrons at the annihilation site. The broadening is characterized by the line-shape parameter S, defined as the central fraction of the 511 keV line. S for a chosen experimental setup has a characteristic value for each annihilation site, for example, for pure bulk Si or for each specific vacancy-type defect, the latter being strong positron traps. The mean depth z of positrons implanted with energy E ͑keV͒ is determined from the relation z = 17.2 E 1.6 nm. Secondary ion mass spectrometry ͑SIMS͒ measurements were performed to determine atomic profiles.Samples used in this study were n-type ͗100͘ Cz Si wafers with a resistivity of 10-20 ⍀ cm. All wafers were first preamorphized with 30 keV, 10 15 cm −2 Ge ions, and implanted with 0.5 keV B ions at 10 15 cm −2 . Half of the samples were additionally implanted with F ions at 10 keV and 10 15 cm −2 , placing the F ions between the B implants and the amorphous-crystalline interface. After restoring the amorphous layer to crystallinity via SPE regrowth ...

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“…This surface charge (N S e) causes a depletion of electrons near the surface and it induces the electric field in the semiconductor [11]. In the simple model used here, the surface charge (N S e) induces a depletion, of length d, created of homogeneous charge density (N d e), such that N S = dN d .…”

Section: Resultsmentioning

confidence: 99%

Amorphous Carbon Thin Films Deposited on Si and PET: Study of Interface States

et al. 2005

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Thin carbon films with various thicknesses, deposited on different substrates (Si and poly-ethylene-terephthalate) at the same operating conditions in a radio frequency plasma enhanced chemical vapour deposition system were characterized by Doppler broadening spectroscopy. The films and the substrates were depth profiled by a slow positron beam. The aim of these measurements was to study the open volume structure and the interface of the films. It was found that, independently from the substrate, the films were homogeneous and exhibited the same open volume distribution. On the contrary, the effective positron diffusion length in the Si substrate was found to change with the thickness of the carbon films. This behaviour was interpreted as a change in the electric field at the carbon/silicon interface.

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Investigation of band bending in silicon by slow positron lifetime measurements

Cited by 13 publications

References 8 publications

A study of the electric field transient at the Au/semi-insulating GaAs contact under an alternating current square-pulse bias

A study of the electric field transient at the Au/semi-insulating GaAs contact under an alternating current square-pulse bias

Fluorine-vacancy complexes in ultrashallow B-implanted Si

Amorphous Carbon Thin Films Deposited on Si and PET: Study of Interface States

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